[0001] The present invention relates to an electronic stringed instrument, and, in particular,
to an electronic stringed instrument which can generate musical tones with multifarious
timbres, when played in the same typical manner as is done with traditional natural
stringed instruments, such as stroking, picking and fingering stretched strings.
[0002] Recently, with rapid improvement of electronic technology, electronic stringed instruments
have been developed and proposed, which can generate musical tones with multifarious
timbres by the same picking technique as is done with traditional natural stringed
instruments. Electronic stringed instruments of this type are classified into a pitch
extracting type and a string triggering type from the view points of the method to
designate a musical tone to be generated and the method to generate the musical tone
with a specified pitch.
[0003] According to the pitch extracting type electronic stringed instruments, the vibration
frequency of a stretched string or the pitch is extracted from the vibration caused
by picking the string, and the pitch of the corresponding musical tone is determined
on the basis of the extracted pitch, and the musical tone with a given timbre is generated
at the determined pitch when the level of the string vibration becomes greater than
a predetermined value.
[0004] According to the string triggering type electronic stringed instruments, the operation
position of a fret presently depressed is detected by a pitch designation operation
status sensor provided on a fingerboard side, the pitch of the corresponding musical
tone is designated by the sensor, the picking operation status with respect to a
string is detected by a string triggering sensor provided on a body side, and a musical
tone with a given timbre is generated by the string triggering sensor at the pitch
designated by the former pitch designation operation status sensor. For this type
of electronic stringed instruments, there are various types of pitch designation operation
status sensors for detecting the fret operation position to designate the pitch of
a musical tone to be generated. For instance, the following types are known:
1) The type which has a number of ON/OFF type fret switches disposed in a matrix form
in the fingerboard.
2) The tablet coordinate detecting type.
3) The type which has a resistance member for each string whose resistance is detected.
4) The type which detects a string-depressed position from electric contact between
a conductive string supplied with a small current and a fret contact.
5) The type which detects the pitch by supplying an ultrasonic wave in strings and
measuring the return time of the wave from a string-depressed position.
[0005] Also, there are various types of string triggering sensors for detecting the beginning
of the string vibration and designating the beginning of tone generation. They include:
1) The magnetic pickup detecting type which magnetically detects the vibration of
stretched strings.
2) The type which detects the axial directional vibration of a string using a Hall
element and a magnet.
3) The string triggering switch type which is actuated by the vibration of a string
to detect the beginning of the string vibration.
4) The piezo-electric element detecting type which detects the string vibration using
a piezoelectric element.
5) The light pickup type which detects the string vibration from the light shielding
state.
[0006] The advantage of the string triggering type electric stringed instruments over the
pitch extracting type lies in their simpler structure such that the beginning of the
string vibration is detected by the string triggering sensor, a musical tone is generated
in response to the detection, and the pitch of the musical tone to be generated is
determined by a pitch designation signal from pitch designation operation status detecting
means.
[0007] On the other hand, the string triggering type has such a prominent shortcoming that
musical tones generated by operating strings do not have rich musical effects or
impressions. Electronic stringed instruments, as they are indeed stringed instruments,
should be able to provide as rich musical impression as can be produced by traditional
stringed instruments, and this is one of the important indices to be good stringed
instruments. To get the index,
A) Electronic stringed instruments should be playable in a manner very similar to
the one involved in traditional stringed instruments, such as guitars, and should
well respond to natural operation.
B) The electronic stringed instruments should produce the same acoustic or musical
effects as can be obtained by the traditional type when played in the same manner.
[0008] However, electronic stringed instruments which can sufficiently fullfil the above
requirement are not yet available because there still are various problems that should
be solved. These problems will be explained below.
[0009] According to conventional, string triggering type electronic stringed instruments,
even when a fret operation position is changed during generation of a musical tone
associated with a triggered string, its sound source does not respond to the change
so that the frequency of the musical tone cannot be changed to the pitch corresponding
to the new fret position. In other words, the conventional electronic stringed instruments
have a limited function to permit generation of a single musical tone for one picking
action. This significantly restricts the playing modes to such a level that the allowable
playing modes or techniques, and hence the resultant musical effects, can be in no
way matched with those of acoustic or electric guitars.
[0010] As a solution to this problem, some of the techniques used in keyboard type electronic
instruments may be applied to the electronic stringed instruments, so that every time
the fret operation position is changed, the generation of a musical tone being generated
can be stopped and a new musical tone can be generated at the pitch corresponding
to the new fret operation position.
[0011] With the use of such a tone generating method, however, when a string is picked with
the right hand and the fret operation is done by sliding the left hand along the string
during tone generation caused by the picking, a new musical tone will be generated
every time the fret operation position is changed. Therefore, if, for example, the
sliding (sliding the left hand along a string) is executed, the electronic stringed
instruments cannot provide a effect similar to the sliding sound effect (only the
pitch varying from one pitch to another) which can be produced from acoustic guitars
by the sliding operation.
[0012] According to conventional stringed instruments using a string triggering switch,
with respect to a string vibration above a given level, the switch temporarily becomes
the ON state, which does not continue; the switch functions in a specific correlation
with the string vibration. For instance, the string triggering switch does not respond
to a very weak string vibration and repeatedly becomes the alternate ON/OFF state
when a large vibration continues.
[0013] Therefore, when the output of the string triggering switch is directly sampled by
a processor such as a microcomputer, the transition between the ON and OFF states
of the switch due to the string vibration cannot be always accurately detected. For
instance, at the beginning of the string vibration, even when the string triggering
switch temporarily becomes the ON state, it is possible that the processor does not
perform the sampling during the ON duration. At the worst, picking of a string is
not detected by the processor. If not the worst, the processor may detect the picking
with such a delay from the operational timing of the string that adverse musical effects
are produced.
[0014] It is desirable that the beginning of tone generation coincide with the string operation
timing or the beginning of the string vibration.
[0015] The above problem can be solved to some degree by sufficiently shortening the interval
between samplings by the processor. This increases the burden of the processor with
respect to an input device, thus requiring a simpler and assured detection of the
string triggering (beginning of the string vibration).
[0016] To realize an electronic stringed instrument having a plurality of strings, the relationship
between the strings and sound sources (which electronically generate musical tones)
should be considered.
[0017] As one approach, one sound source may be assigned to a single string. Assume that
this system is applied to the above string triggering switch type electronic string
instruments. Then, when the switch detects the triggering of one string, the processor
assigns one of plural sound sources to the string and instructs the sound source to
start generating a musical tone at a pitch corresponding to the fret operation position,
which is detected by the fret status detecting means. Consequently, the musical tone
is generated from the sound source. When the same string is triggered again and the
triggering is detected by the switch during generation of the musical tone from that
sound source, the processor instructs the sound source to stop the tone generation
and, upon completion of the tone stopping, instructs the sound source to generate
the musical tone. However, the pitch for the second tone generation corresponds to
the fret operation position detected by the fret status detecting means at that time.
In other words, in this example, when the same string is triggered successively, the
succeeding sound is generated after the previous sound is stopped.
[0018] The above approach cannot regrettably simulate the function of the sound box of a
natural stringed instrument such as an acoustic guitar. According to the stringed
instrument with the sound box, when the same string is successively picked, the generation
of the second musical tone starts while the reverberation of the first musical tone
continues. Such reverberation effect is important property of this type of natural
stringed instruments and gives a good musical impression to a listener. This desirable
reverberation effect cannot be expected from the aforementioned electronic stringed
instruments.
[0019] Further, according to the conventional electronic stringed instruments, the sound
source selects a pitch signal from the fret switch only when supplied simply with
a string triggering signal. The waveform signal with the frequency corresponding to
the pitch signal is formed by a VCO element of the sound source. Meanwhile, an envelope
circuit of the sound source is driven by the string triggering signal and its mode
sequentially changes from attack to decay, release, etc.. The waveform signal of the
above frequency is controlled by the output of the envelope circuit to provide a musical
tone signal. Therefore, the continuous tone-generation time (time from the beginning
of the tone generation until the end of the tone generation) is determined by the
length of an envelope.
[0020] One of the functions of a synthesizer is to generate a musical tone with a number
of timbres. Adding such a function to electronic stringed instruments raises problems
which would not be caused in the case of electronic keyboard instruments.
[0021] One of the problems is concerned with the sound stopping control with respect to
musical tones with timbres of the sustain tone system, such as an organ. The envelope
for typical timbres of the sustain tone system includes a step called sustain. The
sustain step has a fixed envelope value so that the musical tones of the sustain tone
system are kept generated unless a sound stop instruction is sent to an envelope generator
from the processor, etc. In many electronic keyboard instruments, when a key is released,
a key-off signal is generated and sent to the processor, which in turn instructs the
envelope generator to stop the tone generation. For instance, in an organ-sound mode,
an organ sound is kept generated during depression of a key, but it is released to
be stopped when the key is released.
[0022] It is regrettable that the key-off operation is not involved in traditional stringed
instruments. Stringed instruments such as guitars significantly differ from keyboard
instruments such as pianos and organs in mechanics and playing modes.
[0023] As one simple approach to allow the key-off operation in electronic stringed instruments,
they may be designed to have a guitar-like outline but have a keyboard added to provide
a key-off signal when operated. Such instruments cannot, however, be called guitars
any longer and loose the natural properties of stringed instruments such as guitars.
Electronic stringed instruments, as the name stands for, should have a similarity
with traditional stringed instruments at least on the basic level.
[0024] According to traditional natural stringed instruments, with a string depressed by
a finger of one hand, for example, the left hand, the string is stroked or picked
by the right hand, causing the string vibration which generates its associated musical
tone. When the finger is moved off the string, the string vibration is rapidly reduced,
thus rapidly releasing the musical tone being generated. One approach to realize this
phenomenon in electronic stringed instruments is to permit the instruments to electronically
detect the end of the string vibration. This approach is, however, difficult to realize
as it needs a string vibration sensor for accurately detecting the string vibration
and some means for analyzing in real time the output of the sensor and accurately
detecting the real end of the vibration while removing a spurious component included
in the sensor output (for example, a phenomenon which appears as if the vibration
is temporarily stopped). If realized, however, the manufacturing cost would be significantly
high.
[0025] As already described earlier, with the structure of the conventional electronic stringed
instruments, it is not possible to simulate the musical effect (varying only the pitch
without regeneration of a new musical tone) produced by, for example, the sliding,
one of guitar's basic playing techniques, according to which the fret operation position
is sequentially shifted with a finger or fingers of the left hand after a string is
picked by the right hand. (First simulation subject)
[0026] In acoustic guitars or the like, in addition to the sliding, a plurality of strings
are generally used to play a melody. In this case, while one fret of one string is
depressed with a finger of the left hand, the string is picked by the right hand,
and then the finger of the left hand is moved to another string and the new string
is picked by the right hand, and so forth. In the process of moving the finger of
the left hand from one string to another, that finger should naturally be moved off
the first string and the first string goes to the so-called open-string status. This
transition to the open-string status often reduces the string vibration and this
phenomenon is aurally sensed as the stopping of a sound. That is, when a finger is
moved from one string to another to play a melody, the open-string pitch of the first
string is not prominently audible.
[0027] Therefore, to electronically simulate such a basic phenomenon is the second simulation
subject.
[0028] There still exists a difficult problem in the above case. The transition to the open-string
status does not always reduce the string vibration to such a level that the phenomenon
is sensed as sound stopping. For instance, when the fret status is changed from the
first fret to the open-string status, it is likely that the pitch of the open string
is heard following the pitch of the first fret. (If, after moving the finger of the
left hand off the string, the same string is again depressed (sound stop fingering)
or the string is lightly touched with a finger of the right hand, the string vibration
is absorbed by the finger, so that the phenomenon can be sensed as the sound stopping.)
In short, the first simulation subject contradicts the second simulation subject.
[0029] One solution to this contradiction may be to provide the electronic stringed instruments
with an ability to convert the string vibration into an electric signal with a high
fidelity and electrically follow up the behavior of the real string vibration in real
time while removing various spurious or noise components which may be included in
the converted output, whereby a sound source is properly controlled. However, this
approach is difficult to realize at present, and if realized, the products would certainly
be very expensive.
[0030] Natural stringed instruments such as acoustic guitars can be played distinguishing
how much the string vibration should be attenuated or whether the vibration of only
one string or the vibration of all the strings should be stopped, etc., by the way
strings are operated with fingers of the right or left hand (for example, touching
a vibrating string with a finger or a palm). It is, however, extremely difficult to
electronically perform the complete simulation of the above. Even if a sensor for
converting the string vibration into an electronic signal with a relatively high fidelity,
an analyzing device for analyzing the output of the sensor needs to be provided with
an ability to accurately follow up in real time the behavior of the string vibration,
which should finally be reflected on a musical tone, while eliminating the influence
of various spurious components included in the string vibration itself (signal source
itself), whereby the mode of attenuating the string vibration can be distinguished,
for example, through pattern matching. If the above function is realized somehow,
the final products would be very expensive.
[0031] Conventionally, electronic stringed instruments have been known, which has a foot-operable
fast decay petal mounted outside the instrument main body whereby generation of a
musical tone being generated can be rapidly be stopped by operating the fast decay
petal with a foot, as disclosed in U.S. Patent No. 4,336,734.
[0032] Since, in the above electronic stringed instruments, rapid stopping of the tone
generation should be executed by operating the fast decay petal disposed at a player's
foot, the instruments can only be played where the fast decay petal is disposed. This
restriction does not permit the player to play the electronic stringed instruments
while moving around.
[0033] The present invention has been devised to solve the aforementioned various conventional
problems and its objects are as follows.
[0034] It is an object of this invention to provide an electronic stringed instrument, which
can accurately and quickly detect the vibration of a string caused by picking the
string, with a simple structure.
[0035] It is another object of this invention to provide an electronic stringed instrument
which, when the fret operation position is changed during generation of a given musical
tone caused by picking a string, can change the pitch of the generated musical tone
to the pitch corresponding to the new fret operation position without generating a
new musical tone.
[0036] It is a still another object of this invention to provide an electronic stringed
instrument which, when the same string is stroked successively in a short period of
time, can generate a succeeding musical tone while reverberation of the previously-generated
musical tone continues, thus providing a sufficient tone reverberation effect.
[0037] It is a further object of this invention to provide an electronic stringed instrument
which can stop generation of a musical tone immediately upon elapse of a predetermined
time from the beginning of the tone generation, irrespective of whether the generated
musical tone is of a sustain tone system or a release tone system.
[0038] It is a still further object of this invention to provide an electronic stringed
instrument which, when the fret operation status is changed to an open-string operation
status after picking of a string, can stop all the presently-generated musical tones
or that musical tone whose associated string is changed to the open-string operation
status.
[0039] It is a still further object of this invention to provide an electronic stringed
instrument which, when a given fret operation status is changed to an open-string
operation status, can determine whether the presently-generated musical tone is to
be rapidly released from the timing at which the transition to the open-string operation
status is made or the pitch of the musical tone is to be changed to the one corresponding
to the open-string operation status from the above timing, in accordance with the
intention of a player.
[0040] It is a still further object of this invention to provide an electronic stringed
instrument which can freely stop all or a part of the presently-generated musical
tones at an arbitrary timing with a simple manual operation by a player while the
player, moving around, is playing the instrument.
[0041] This invention can be more fully understood from the following detailed description
when taken in conjunction with the accompanying drawings, in which:
Fig. 1 is an overall perspective view of an electronic stringed instrument according
to one embodiment of this invention;
Fig. 2 is a cross-sectional view taken along line II-II of Fig. 1;
Fig. 3 is a cross-section view taken along line III-III of Fig. 2;
Fig. 4 is an overall diagram of an electronic circuit used in this invention;
Fig. 5 is a general flowchart of this invention;
Fig. 6 is a diagram for explaining a string triggering detecting function;
Fig. 7 is a diagram for explaining a pitch change function;
Fig. 8 is a diagram for explaining a tone reverberation function;
Fig. 9 is a diagram for explaining a sound stop function executed upon elapse of a
sounding time of a musical tone;
Fig. 10 is a diagram for explaining a sound stop function executed when the transition
to an open-string operation status is made;
Fig. 11 is a diagram for explaining a tone muting function;
Fig. 12 is a diagram illustrating the structure of a latch circuit;
Fig. 13 is a diagram illustrating registers associated with string triggering detection;
Fig. 14 is a detailed flowchart of a string triggering detection process;
Fig. 15 is a flowchart of an interrupt routine involved in resetting the latch circuit;
Fig. 16 is a diagram illustrating sound source control registers;
Fig. 17 is a detailed flowchart of a sound source assigning/sound generating process
shown in Fig. 14;
Fig. 18 is a flowchart for setting the sounding time;
Fig. 19 is a flowchart of an interrupt routine associated with a sounding time control;
Fig. 20 is a detailed flowchart of a fret status detecting process;
Fig. 21 is a detailed flowchart of a frequency change process shown in Fig. 20;
Fig. 22A is a diagram illustrating the switching between the frequency change function
and open-string sound stop function, which is executed by a release string mode select
switch;
Fig. 22B is a flowchart with respect to a release string mode select switch input;
Fig. 23 is a flowchart with respect to a mute switch input;
Fig. 24 is a detailed flowchart of a full sound source stop process shown in Fig.
23;
Fig. 25 is a diagram illustrating registers associated with frets;
Fig. 26 is a flowchart of a fret status change process;
Fig. 27 is a flowchart of a frequency change process;
Fig. 28 is a flowchart of a muting process; and
Fig. 29 is a plan view of an electronic stringed instrument according to another embodiment
of this invention.
[0042] An embodiment of this invention will now be explained with reference to the accompanying
drawings.
[Instrument Main Body (Fig. 1)]
[0043] Fig. 1 shows the main body of an electronic stringed instrument according to this
embodiment. As illustrated, the main body of the stringed instrument has a body 1,
a neck 2 and a head 3, with a plurality of strings 4 stretched along the length of
the main body. Body 1 has parameter setting switches 5 for setting various parameters.
The switches 5 include timbre select switches 5a, a mute switch 5b, a string release
mode select switch 5c and a mute reserve switch MSW. Also, rhythm pad switches 6 are
provided as operation elements for manual rhythm performance. Inside body 1 is a
speaker disposed to generate played musical tones.
[0044] Each string 4 has one end adjustably supported by its associated peg 7 provided on
head 3, and has the other end extending on a fingerboard 8 to a string trigger switch
case 11 disposed on a rear portion of body 1 and fixed in the case 11. On fingerboard
8 are fret switches FSW provided in a matrix form for pitch designation; when strings
4 between frets 12 are depressed, the associated fret switches FSW are turned on.
A detailed description of the fret switches FSW will be given later.
[0045] Case 11 accommodates string trigger switches TSW, which are coupled to the associated
strings 4 in such a manner that picking or fingering strings 4 turns the associated
string trigger switches TSW on, thereby starting the sounding of the musical tones.
A detailed description of the string trigger switches TSW will be given later.
[Fret Switches (Fig. 2)]
[0046] Fig. 2 exemplifies the structure of fret switches FSW. As illustrated, a printed
board 13 and a rubber sheet 14 are fit and fixed in a recessed section 2a formed in
the top of neck 2. Rubber sheet 14 is adhered on printed board 13 and have its either
end bent in a U shape to accommodate the associated end of printed board 13 so that
the board 13 is fixed. Six rows of contact recesses 15 are formed along the length
of neck 2 at locations corresponding to the individual strings 4 at the bottom of
rubber sheet 14, which is adhered to the top of printed board 13. A pattern of electrodes
16 serving as movable contacts is formed on the bottom surfaces of recesses 15, and
a pattern of electrodes 17 serving as stationary contacts is formed on printed board
13, the electrodes 17 facing the associated electrodes 6. Each electrode 17 and its
associated electrode 16 constitute a fret switch FSW. When strings 4 on fingerboard
8 are depressed rubber sheet 14, hence depressing rubber sheet 14, electrodes 16 are
made to have an electric contact with electrodes 17 so that fret switches FSW are
turned on.
[String Trigger Switches (Fig. 3)]
[0047] Fig. 3 exemplifies the structure of string trigger switches TSW. As mentioned earlier,
string trigger switches TSW are turned on or off by strings 4 on body 1. As illustrated
in Fig. 3, on body 1 is disposed a switch mounting table 18, which has a projecting
section and a support section 18a provided on the upper portion of the projection
section. In support section 18a are grooves 18b formed whose number corresponds to
the number of strings 4. A metal contact plate 19 is attached to the rear edge portion
of support section 18a, and has through holes 19a formed therein at positions corresponding
to the individual strings 4. Conductive members 20 integrally coupled to the respective
strings 4 are fit in the associated through holes 19a. Each conductive member 20 is
a circular metal rod with a predetermined length and has an engage hole 20a at its
distal end where the associated string 4 is engaged. Each conductive member 20 further
has a first stop ring 20b provided at the rear portion of the engage hole 20a and
a second stop ring 20c separated by a predetermined distance from the former ring
20b. The first and second stop rings 20b and 20c are provided to prevent a pair of
insulative members 21, provided on the associated conductive member 20 with a predetermined
interval therebetween, from moving in the lengthwise direction of conductive member
20. Both insulative members 21 and 21 have stepped portions facing each other, and
a spring coil 22 serving as a flexible conductive member is bridged between the two
stepped portions. Each conductive member 20 has a support shaft 20d formed at that
portion thereof which extends from the back of second stop ring 20c and is narrower
than the remaining portion. The end portion of support shaft 20d is fit in the associated
groove 18b of support section 18a and the associated through hole 19a of contact plate
19, and is engaged with a stopper 23 having a semi-sphere distal end portion, in a
slidable manner around the through hole 19a. That is, each conductive member 20 has
its rear end slidably engaged with support shaft 20d and the other, free end supported
to be stretched by its associated string 4. Projecting pieces 19b, formed at the
top portion of contact plate 19 in correspondence with through holes 19a, are fixedly
fit in predetermined locations of a printed board 24 provided on support section
18a and are coupled to a wiring pattern formed on printed board 24, by means of solder
19c. A lead wire 22a extending from one end of each coil spring 22 coupled through
insulative members 21 to conductive member 20 is also coupled to another wiring pattern
formed on printed board 24, by means of solder 22b.
[0048] The illustrated trigger switches TSW, described above, each have conductive member
20 as the first contact and coil spring 22 as the second contact. In normal state,
a space corresponding to the thickness of insulative member 21 is kept between coil
spring 22 and conductive member 20. When a vibration of a certain degree or more is
caused by operating string 4, however, coil spring 22 vibrates due to the vibration.
As a result, the space between conductive member 20 and coil spring 22 varies with
time and the member 20 and spring 22 repeat contact and non-contact states. In other
words, trigger switch TSW is repeatedly turned on and off. As will be described later,
according to this embodiment, the status change of this trigger switch TSW toward
the first ON state (i.e., triggering of string 4) can be assuredly detected.
[Overall Circuit Arrangement (Fig. 4)]
[0049] Fig. 4 illustrates the overall circuit arrangement of an electronic stringed instrument
according to this embodiment. The general control of the instrument is performed by
a microcomputer 30. The outputs of trigger switches TSW are supplied to a latch circuit
40 and microcomputer 30 detects the triggering of strings 4 through this latch circuit
40. The status of each fret switch FSW and the status of each of panel switches PSW
(various switches provided on body 1, such as parameter setting switches 5 and rhythm
pad switches 6, as shown in Fig. 1) are reported to microcomputer 30 through a switch
status detection circuit 50. A musical tone generating circuit 60 generates a musical
tone signal under the control of microcomputer 30. The generated tone signal is amplified
in an amplifier 70 and is output as a sound through a speaker SP.
[General Flow of Microcomputer (Fig. 5)]
[0050] Fig. 5 illustrates the general flow of microcomputer 30 (see Fig. 4). When the instrument
is powered up, microcomputer 30 executes initializing step G1 first, and then repeats
steps G2 through G8. In string triggering detection step G2, microcomputer 30 reads
the output of latch circuit 40 (Fig. 4) and determines whether or not there is the
triggering of each string 4. When the string triggering (start of vibration of the
strings) is detected, microcomputer 30 causes musical tone generating circuit 60 to
generates a musical tone. In fret status detection step G3, microcomputer 30 reads
the status of each fret switch FSW through switch status detection circuit 50. Then,
a change in fret status (change in pitch designation) is determined in fret status
change discrimination step G5, and if the change exists, fret status change step G5
is performed. IF the string-depressing position of a fret belonging to that string
which is presently producing musical sounds is changed, the pitch of the string is
set again to the pitch corresponding to the change (this process being performed with
respect to that sound source module in musical tone generating circuit 60 which is
producing the musical sound of the string) in step G5. If the fret status is changed
to a so-called open string status where any fret switch FSW belonging to the sound-producing
string is at the OFF state, a sound stop operation is performed. No process is done
with respect to a change, if any, in the string-depressing positions of frets belonging
to those strings which are presently producing no sounds. In the next panel switch
status detection step G6, microcomputer 30 reads out the status of each panel switch
PSW through switch status detection circuit 50. In panel switch status change discrimination
step G7, a change in status of a panel switch is discriminated, and if the decision
is affirmative, a desired process, for example, setting the timbre, effect or the
like to musical tone generating circuit 60 is performed in the subsequent panel switch
status change step G8.
[Features of the Embodiment]
[0051] Before going into the detailed descriptions of the individual features, several features
of the embodiment will now be given briefly.
[0052] The first feature is an assured detection of string triggering, whose principle is
illustrated in terms of waveforms in Fig. 6. Fig. 6a illustrates a model vibration
waveform of strings 4, and Fig. 6b illustrates the status of string trigger switches
TSW with respect to this string vibration. As should be clear from comparison between
these two waveforms, string trigger switches TSW are repeating the ON and OFF states
in accordance with the vibration. When the vibration of strings 4 is reduced by a
certain degree or more, string trigger switches TSW are rendered inactive and become
the OFF state. Simple sampling of the outputs of such string trigger switches TSW
cannot ensure assured and accurate detection of the start of the string vibration
or the string triggering.
[0053] According to this embodiment, therefore, as indicated by the latch output shown
in Fig. 6c, a change in the status of string trigger switches TSW to the first ON
state is held by the latch circuit and the content of this latch circuit is sampled
by microcomputer 30, thereby detecting the string triggering. Further, upon elapse
of a predetermined time after the detection, microcomputer 30 supplies a latch reset
signal as shown in Fig. 6d to the latch circuit to reset it.
[0054] The second feature is to change only the pitch in the case where the fret operating
position is changed to another position during the sounding of a musical tone. The
principle of this feature is illustrated in Fig. 7. Assume that stroking any string
is done, the associated string trigger switch is turned and the triggering of that
string is detected, as indicated in Fig. 7a. Upon detection of the ON state of the
string trigger switch, sounding of a musical tone starts. At this time, the fret operating
position of the triggered string is checked in order to determine the pitch of the
musical tone to be sounded. Here, the fret status detection means or fret switch FSW
for detecting the fret operating position of the triggered string is indicating the
status for designating pitch A, as shown in Fig. 7b. Consequently, the start of sounding
a musical tone with pitch A as the musical tone of the triggered string is designated
with respect to a sound source (not shown) and a musical tone waveform having a frequency
of pitch A is generated in the sound source, as shown in Fig. 7c.
[0055] Assume now that, while the musical tone of the triggered string is being generated,
another fret position belonging to this string is depressed so that the pitch designation
status is changed to the one which designates pitch B, as indicated in Fig. 7b. In
response to this change, musical tone generating means controls the sound source
to change the pitch to pitch B without stopping the sounding of the presently-generated
musical tone of the triggered string. As a result, as shown in Fig. 7c, simply a musical
tone waveform whose frequency is changed to correspond pitch B is generated from the
sound source, not a new musical tone.
[0056] As described above, according to this invention, the sounding of a musical tone of
a stroked string, once started, is not stopped by a succeeding change in fret operating
position, nor is the sounding of a new musical tone started by the change in fret
operating position. Only, the frequency or the pitch of the generated musical tone
is changed in accordance with the change in fret operating position. Therefore, it
is possible to play a gentle phrase which does not have any attack except the one
caused at the start of the sound generation by a picking action, so that the same
musical effect as attained by a typical guitar can be produced by the same playing
procedure as involved in playing such a guitar.
[0057] The "pitch designation change" shown in Fig. 7b may apply not only to the case of
a physical change from one fret position to another, but also to the case where the
so-called open-string status (which is used to indicate what the term "open string"
normally means with respect to a guitar) is changed to the fret-depressed status at
which a fret is depressed, and vice versa. In this case, fret status detection means
is designed to be able to detect the open-string status at which no physical fret
positions belonging to a triggered string are depressed. And, this design can be easily
realized.
[0058] The envelope characteristic of the musical tone waveform (indicated by the envelope)
hardly varies before and after the frequency change, thus causing an entirely gentle
pitch change. If desired, however, the envelope of the musical tone after the frequency
change may be caused to have a slight attack, or the envelope of the musical tone
before the frequency change may be caused to slightly fall and the envelope after
the change may be caused to rise to the original level.
[0059] The third feature is the function of reverberation of a musical tone generated by
successively picking the same string 4 in a short period of time. This function is
realized by a different sound source assign/sounding function performed by microcomputer
30. Fig. 8 illustrates the principle of the reverberation function.
[0060] Assume that the first triggering of one string 4 is detected by the turning on of
a string trigger switch TSW, as shown in Fig. 8a. In response to the detected status,
microcomputer 30 finds out a sound source to generate the intended sound and request
the found sound source (source 1 in this case) to start generating the sound. As a
result, sound source 1 produces the first musical tone waveform (the left one) shown
in Fig. 8b and the generation of the musical tone corresponding to the triggered string
4 starts. Assume now that the same string 4 is stroked again during generation of
the musical tone corresponding to that string 4 (see the second ON point in Fig.
8a). In response to the retriggering of the same string, microcomputer 30 requests
that sound source 1, which is generating the previous musical tone, should stop the
generation of the musical tone, and at the same time assigns a sound source 2 different
from sound source 1 to generate a musical tone corresponding to the retriggered string.
As a result, after the retriggering action, while the previous musical tone being
presently generated by sound source 1 is released by the source 1, the succeeding
musical tone is generated by sound source 2 and its waveform starts rising (see Fig.
8b). This provides an effect similar to the reverberation effect which can be produced
by a sound box of an acoustic guitar, etc.
[0061] The fourth feature is a sound stop function performed on the basis of the elapse
of a sounding time. Specifically, in response to the picking operation of a string,
microcomputer 30 measures a predetermined time from the start of the sounding operation
and executes the sound stop operation upon elapse of the predetermined time. The
principle of this function will be explained below referring to Fig. 9. When a string
4 is triggered as shown in Fig. 9a and the triggering is detected, microcomputer 30
request a sound source (one of sound source modules in musical note generating circuit
60) to start generating a sound (which has already been described earlier). At the
same time, microcomputer 30 starts measuring the time the sound source is generating
the sound. Consequently, a musical tone is generated by the sound source as shown
in Fig. 9c. In the case of Fig. 9, even when measuring the sound generating time indicated
in Fig. 9b is completed, the sound source keeps generating the musical tone. Upon
elapse of the sound generating time, microcomputer 30 requests that the sound source
stops the generation of the musical tone. Consequently, the sound source enters the
release mode and performs rapid release of the musical tone to thereby stop generating
the sound, as indicated in Fig. 9c.
[0062] The broken line shown in Fig. 9c indicates the musical tone waveform which would
be attained if the sound stop request is not made to the sound source upon elapse
of the sound generating time.
[0063] When a fixed sustain is included in the envelope of a musical tone waveform, the
musical tone is normally kept generated endlessly if no sound stop request is made.
As should be understood from the above explanation, however, according to this invention,
the sound stop request is made to the sound source to forcibly stop the sound generation
upon elapse of a predetermined sound generating time after the string triggering,
thus completely overcoming the conventional problem of endless sound generation.
[0064] According to one preferred structure, independent sound generating times are set
for different timbres. For instance, with respect to the timbre of an organ, the sound
generating time is set to be relatively longer so as not to loose the natural sounds
of the organ. Such time setting can be made by makers or can be programmed such that
the sound generating times can be varied by users in accordance with different timbres.
In this case, artificial selection of a sound generating time sorter than the natural
one can provide a musical tone of a different timbre.
[0065] According to another arrangement, identification data for discriminating whether
the timbre is of a sustain tone system or a release tone system is provided such that,
only when the presently selected timbre is of the sustain tone system, the sound generating
time needs to be measured and the sound stop request should be made upon elapse of
the time.
[0066] The fifth feature is a string-based sound stop function which stops only the presently-generated
musical tone for each string when the fret status is changed from a string-depressed
status to an open-string operated status (the state in which every fret switch belonging
to the triggered string is OFF, i.e., the open fret state). This function produces
an effect similar to the one often obtained by playing an acoustic guitar, etc., i.e.,
by lightly depressing a vibrating string with left fingers, etc. to stop the vibration,
thereby stopping the generation of a musical tone originated from the string vibration.
[0067] The principle of the above function will be explained below with reference to Fig.
10. Assume now that the triggering of a string 4 is detected by the ON state of the
associated string trigger switch TSW, as shown in Fig. 10a. Then, in response to this
detection, microcomputer 30 selects the proper sound source module in musical tone
generating circuit 60 and request the module to generate a musical tone with the pitch
corresponding to the position of the presently-selected fret (which has already been
described earlier). In Fig. 10, at the string-triggered point (where the string trigger
switch input is ON), any fret switch belonging to the triggered string is at the ON
state or at a non-open-string operated state. Accordingly, a musical tone waveform
as shown in Fig. 10c is generated in the sound source module with the pitch corresponding
to the turned-on fret switch. Then, when the string-depressing finger is moved off
the fret position during generation of the musical tone corresponding to the string
and the presently-actuated fret switch is turned off to be at the open-string operated
state, as shown in Fig. 10b, microcomputer 30 makes a sound stop request to the sound
source module which is presently generating a musical tone signal. This sets the sound
source module to be in the release mode so that it performs the rapid release of the
presently-generated musical tone to stop the generation of the sound.
[0068] The sixth feature is a full string sound stop function which stops the generation
of all the musical tones generated by all the triggered strings when all strings become
the open-string operated state as a result that the fret operating position of an
arbitrary string or the fret operating positions of plural strings are changed to
the open-string operated state. This function can ensure that the generation of the
musical tones of all the strings is stopped at a time only by the fingering operation
of left fingers. For instance, when a player giving a chord performance performs the
picking of all or a plurality of strings while depressing a specific string at a given
fret position with a left finger, e.g., a left middle finger, those strings other
than the one depressed with the middle finger starts producing musical tones with
the pitches attained by open strings and the finger-depressed string starts generating
a musical tone with the pitch corresponding to the fret position. If, in the above
case, the left middle finger is also moved off the fret, all the strings become the
open fret state (i.e., any fret of every string being at the open state) in accordance
with the fret opening. At the full string open state, every fret switch FSW is at
the OFF state. When informed of this full string open state, microcomputer 30 takes
it as a full string sound stop request and causes all the presently-generated musical
tones to be stopped. As a result, all the sound sources (those sources which are presently
generating sounds) provided for the strings simultaneously enter the release mode
and release the presently-generated musical tone signals. According to this example,
the time from the point at which the string status is changed to the full string open
status due to the fingering done by the left finger of the player to the point at
which stopping the generation of the musical tones of all the strings in the instrument
starts is negligible and a significantly high response is attained, thus ensuring
simultaneous stopping of the generation of all the musical tones.
[0069] This function ensures a clear-cut performance such as staccato. Further, since this
function is initiated by easy fingering done on the fingerboard by left fingers, the
music performing operation is so simple and easy that even a novice can handle the
function hardly with any problem. In addition, the function can greatly apply to the
simulation of performances for an acoustic guitar, etc.
[0070] The string-based sound stop function performed under the condition that the string
status is changed to the open string status from the string-depressed status as described
earlier with reference to Fig. 10 and the pitch changing function performed under
the condition that the fret status is changed from the string-depressed status (fret-operated
status) to another fret operated status as described earlier with reference to Fig.
7 can be fully and independently performed when the pitch changing conditions do not
include the transition to the open-string operated status. However, when the transition
to the open-string operated status belongs to the pitch changing conditions (one of
the changes in fret status), there will be a contention between the pitch changing
function and the string-based sound stop function, only with regard to this change.
It is significantly desirable for the performer that the response of a musical tone
to the transition from the depressed-string operated status to the open-string operated
status be varied depending on the state of the performance. More specifically, various
performance needs of a performer can be met if, upon occurrence of the transition
from the depressed-string operated status to the open-string operated status, under
one circumstance, the generation of a presently-generated musical tone is stopped
from the point of time at which the transition is made, and if, upon occurrence of
the same transition, but under a different circumstance, the pitch of the musical
tone corresponding to the depressed-string operated status is changed to the one corresponding
to the open-string operated status when the transition occurs.
[0071] According to this embodiment, therefore, to satisfy these requirements, string release
mode select switch 5c, which can be operated, as desired, by a performer, is provided
in the instrument's main body. When a mode to select the open string sound stop function
is specified by this mode select switch 5c, as shown in Fig. 22A, selection means
selects the open string sound stop function 300, not the pitch change function 200
at the time of the transition from the depressed-string operated status to the open-string
operated status. As a result, the sounding of the presently-generated musical tone
is stopped. On the other hand, when a mode to select the pitch change function is
specified by mode select switch 5c, the selection means selects the pitch change function
200 by priority with respect to the transition to the open-string operated status.
Consequently, the pitch of the presently-generated musical tone is changed to the
one corresponding to the open-string operated status. The above-described string
release mode select function is the seventh feature of this embodiment.
[0072] The eighth feature is a rapid sound stop function which ensures rapid sound stop
by a manual operation as well as ordinary sound stop, which is initiated when ordinary
sound stop conditions are satisfied. The principle of this function is illustrated
in Fig. 11. As described above, the generation of a musical tone starts when a string
trigger switch TSW is turned on as shown in Fig. 11 (specifically, see Figs. 11a and
11c). In the case of Fig. 11, however, mute switch 5b (see Fig. 1) is depressed during
generation of the musical tone. In response to this depressing action, microcomputer
30 makes a rapid sound stop request to the sound source module which is generating
the musical tone signal. Upon receipt of this request, the sound source module rapidly
release the generated musical tone signal to stop the sound generation.
[0073] The addition of such a rapid sound stop function can provide an acoustic effect similar
to the one attained by the cutting technique of an acoustic guitar, etc.
[0074] It is illustrated in Fig. 11 that the actuation of mute switch 5b influences only
a single musical tone waveform; however, in an example to be described later, when
mute switch 5b is turned on, the rapid sound stop request is made to all the sound
source modules which are generating musical tones. That is, all of the presently-generated
musical tones are simultaneously subjected to rapid muting.
[0075] The ninth feature is a mute reserve function performed by mute reserve switch MSW
(see Fig. 1). With this function, once mute reserve switch MSW provided in the instrument's
main body is operated in advance to reserve the muting, when a predetermined time
elapses after generation of a musical tone by picking a string, sounding of the musical
tone of the string is rapidly stopped. (The time is measured by a counter or timer
means.) In response to a vibration start signal from string trigger switch TSW, microcomputer
30 causes the sound source to generate the musical tone of the triggered string and
activates the timer means to measure the elapse of the predetermined time. If the
muting has been assigned in advance, microcomputer 30 requests the sound source to
rapidly stop generating the sound upon occurrence of the time-out of the timer means.
This puts the sound source to the rapid release mode so that the generated musical
tone signal is rapidly released. This arrangement can very easily provide an acoustic
effect similar to the muting effect which is produced by an acoustic guitar, etc.
[0076] The following detailed explanation will make it apparent as to how the above explained
characterizing functions and other functions are specifically realized.
Latch Circuit (Fig. 12)
[0077] Fig. 12 illustrates an example of the structure of latch circuit 40 shown in Fig.
4, which is used to realize the first feature of this embodiment, i.e., the accurate
string triggering detection function. In the figure, TRI1 to TRI6 are the outputs
of string trigger switches TSW respectively provided to the first to sixth strings
4. For instance, TRI1 is the output of the string trigger switch TSW of the first
string. The individual switch outputs TRI1 to TRI6 become "L" by the ON states of
the respective string trigger switches TSW and become "H" by their OFF states. These
switch outputs TRI1-TRI6 supplied through their respective inverters I1-I6 to the
inputs of their associated latch circuits 40-1 to 40-6, which are designed to function
as RS flip-flops. The transition of the level from "H" to "L" of switch outputs TR1-TR6
sets the associated latch circuits 40-1 to 40-6 so that the outputs TR01-TR06 of the
set latch circuits become "H." That is, when a string trigger switch TSW is turned
on for the first time, the associated one of latch circuit 40-1 to 40-6 is set and
the output of the latch circuit is thereafter kept at "H." The individual latch outputs
TRO1-TRO6 are periodically sampled by microcomputer 30 in the string triggering detection
step G2 shown in Fig. 5 (whose detailed description will be given later). As will
be described later, microcomputer 30 detects the string triggering by detecting a
change in the status of each latch circuit from the reset status ("L" state) to the
set state ("H" state) and controls the timing of musical tone generation. After detecting
the string triggering, microcomputer 30 also measures the elapse of a predetermined
time and resets latches circuits 40-1 to 40-6 through the associated latch reset inputs
CR1 to CR6 shown in Fig. 12 upon elapse of that time.
Registers Involved In String Triggering Detection (Fig. 13)
[0078] Fig. 13 illustrates a part of a group of registers which are provided in microcomputer
30 and used for detecting the string triggering. The register denoted by RTBIT is
used to store previous sampled values of the individual outputs of the aforementioned
latch circuits 40-1 to 40-6. As illustrated, the least significant bit of register
RTBIT holds the previous sampled value of the first latch circuit 40-1, the second
bit of the register holds the previous sampled value of the second latch circuit 40-2,
and so forth up to the sixth bit holding the previous sampled value of the sixth latch
circuit 40-6. Registers RSTCT1 to RSTCT6 are reset counters used to measure the time
for resetting the associated latch circuits 40-1 to 40-6 upon detection of the string
triggering. For instance, when the triggering of the first string is detected through
latch circuit 40-1, a predetermined value is set in the first reset counter RSTCT1,
and is down-counted for each predetermined time interval. When a borrow is output,
i.e., when the reset counter underflows, a reset signal is sent to latch circuit 40-1.
Triggering Detection Process (Fig. 14)
[0079] Fig. 14 is a detailed flowchart of the triggering detection step G2 (Fig. 5). First,
in step P1, latch circuit outputs TRO1-TRO6 shown in Fig. 12 are latched in an accumulator
ACC of microcomputer 30. The sampled values TRO1 to TRO6 are set in accumulator ACC
respectively from the least significant bit to the sixth bit, leaving the highest
two bits unused. Registers ACC, B-RG, C-RG and D-RG are each of 8 bit capacity. In
the next step P2, the illustrated processes are executed. In this step, "EXOR" indicates
an exclusive OR operation while "AND" indicates a logical product. Through the step
P2, the sampled values of the present latch outputs are saved in register D-RG, and
the first to sixth bits of register C-RG are respectively set with "H" or "1" only
when the sampled values of the associated, previous latch outputs are "L" but the
sampled values of the corresponding present latch outputs are "H," and are set with
"L" or "0" otherwise. As a string number, "1" indicating the first string is set in
register B-RG.
[0080] The loop from steps P3 to P10 executes the triggering process from the values of
the individual bits of register C-RG. In step P3, register C-RG is right shifted by
one (in the direction from higher bits to lower bits) and the most significant bit
MSB of register C-RG is set with "0" and bit CARRY is set with the value of the least
significant bit LSB. The value of CARRY is discriminated in the next step P4. CARRY=1
in step P4 indicates that some string is triggered (more specifically, the first
ON state of string trigger switch TSW of one string is detected through latch circuit
40) and the number of the triggered string is given by string number register B-RG.
If CARRY=1 in step P4, the flow advances to step P5 where a predetermined value (time
data for resetting the latch circuit) is set in the reset counter RSTCT corresponding
to the value of register B-RG. In the next step P6, of the pitch data of the individual
strings which is saved in the fret status detection step G3 as shown in Fig. 5, the
pitch data of the string number indicated by the value of register B-RG is loaded
in register P-RG. Then, the flow advances to step P7 where assigning a sound source
of musical tone generating circuit 60 (Fig. 4) and generating a sound are executed
in accordance with the string number 1 and the pitch data.
[0081] After step P7 or when CARRY=0 in step P4, the flow advances to step P8 where the
value of register B-RG is incremented by one to advance the string number by one.
In the next step P9, it is determined whether or not the value of register B-RG is
equal to or less than 6, and if it is equal to or less than 6, the flow returns to
step P3 and repeats the above-explained loop.
[0082] When the loop process is completed for all the strings, the flow advances to step
P10 where the presently-sampled latch output or the content of register D-RG is saved
in register RTBIT. The saved data is used as the previous sampled value in step P2
when the next triggering detection flow (Fig. 14) is executed.
Latch Reset Process (Fig. 15)
[0083] As described above, time data for resetting the latch circuit is set in reset counter
RSTCT (Fig. 13) of a triggered string in step P5 of the triggering detection flow
(Fig. 14). With regard to this step, microcomputer 30 performs a process for resetting
latch circuits 40-1 to 40-6 upon elapse of a predetermined time from the point of
time when the string triggering has started, in a time interrupt routine to send an
interrupt signal at a predetermined interval. Fig. 15 illustrates the flow of the
latch resetting process (time interrupt routine). The steps Q1 to Q3 are the sequence
of the latch resetting process for the first string. In step Q1, it is determined
whether or not the first bit of register RTBIT is "1" in order to discriminate whether
or not the first latch circuit 40-1 (see Fig. 12) corresponding to the first string
is set. If the decision is affirmative in this step, the flow advances to step Q2
where reset counter RTCT1 of the first string is down-counted and if there is a borrow,
the first bit of register RTBIT is set to "0" so as to output a low pass to latch
reset line CR1 of the first latch circuit 40-1. As a result, latch circuit 40-1 is
reset.
[0084] Similarly, the latch reset steps Q4-Q18 for the second to sixth strings are performed.
[Review of String Triggering Detection Function]
[0085] By now it should be understood that the present embodiment has an assured string
triggering detection function. When each string 4 (Fig. 1) starts vibrating, the associated
string trigger switch TSW (Fig. 3) is switched on, thus setting the associated one
of latch circuits 40-1 to 40-6. At the time of the next latch data sampling after
the latch setting process, microcomputer 30 (Fig. 4) executes the triggering detection
process as shown in Fig. 14 and detects which string is triggered from the result
of comparison between the present and previous latched samples. Based on the detection,
microcomputer 30 executes the process for starting the sound generation, etc. (see
steps P6 and P7) and sets the reset counter RSTCT (Fig. 13) of the triggered string
in step P5. The reset counter RSTCT is down-counted upon every occurrence of an interrupt
in the latch reset process (time interrupt routine) as shown in Fig. 15. Consequently,
when a predetermined time elapses after the triggering of the string, the reset counter
RSTCT underflows and that one of latch circuits 40-1 to 40-6 which is associated with
the triggered string is reset (see step Q3, for example). Therefore, the string triggering
detection function described with reference to Fig. 6 is surely realized.
Assign/Sounding Process (Figs. 16 and 17)
[0086] The sound source assigning/sound generating step P7 in the flow of Fig. 14 will now
be explained in detail.
[0087] In the sound source assigning/sound generating step, microcomputer 30 (Fig. 4) controls
the generation of a musical tone of the triggered string and also realizes the third
feature of this embodiment, namely, the tone reverberation function when the same
string is picked in succession.
[0088] Before going into the explanation of the detailed flow of the sound source assigning/sound
generating step, some of registers used in this flow will be explained below.
[0089] Fig. 16 illustrates the control registers for the individual sound source modules
of musical tone generating circuit 60 (Fig. 4). (In this example, circuit 60 is constituted
by eight sound source modules.) In Fig. 16, eight registers MODULE1 to MODULE8 respectively
correspond to sound source modules No. 1 to No. 8 of musical tone generating circuit
60, and each control register comprises a string number designation register a, a
pitch designation register b and a sounding time control counter c. String number
designation register a is written with a value corresponding to the number of the
string generating a musical tone, e.g., "1" for the first string. If this value is
zero, however, it indicates that the associated sound source module is not presently
used for tone generation. Pitch designation register b is written with pitch data
of the presently-generated musical tone. Sounding time control counter c is for measuring
the elapse of the tone generation time from the start of the tone generation and is
set with a predetermined value when the associated sound source generates a sound.
Register LASTMD is used for assigning a sound source module and its function will
be explained later.
[0090] In Fig. 17, sound source number designation register D-RG holds a value corresponding
to the number of a sound source module and loop count register E-RG is for counting
the loop.
[0091] The flow of the sound source assigning/sound generating step will be explained referring
to Fig. 17.
[0092] The first half (R1-R7) of the flow is for searching the individual sound source modules
of musical tone generating circuit 60 for the one which has already generated the
musical tone corresponding to the presently triggered string, and requesting, if
found, that sound source module to stop the tone generation. The second half (R8-R18)
of the flow is for finding a sound source module (unused module) to newly generate
the musical tone corresponding to the presently triggered string and requesting that
module to start generating the musical tone.
[0093] In the first step R1, a value "1" indicating sound source module No. 1 is written
in sound source number designation register D-RG. In other words, sound source module
No. 1 is designated. In step R2, the contents of string number designation register
a of the sound source module control register, which corresponds to the value of register
D-RG is loaded. In other words, the number of the string whose musical tone is presently
generated from the presently designated sound source module No. 1, is read out. Then,
in step R3, the value of string number designation register B-RG which indicates the
number of the presently-triggered string is compared with the number of the string
whose musical tone is generated by the presently-designated sound source module No.
1. If the compared values are not equal to each other, it means that the presently-designated
sound source module No. 1 is not generating the musical tone corresponding to the
presently-triggered string. In this case, this module No. 1 is either generating the
musical tone of another string or is not generating any tone and is not busy. In this
case, the value of register D-RG is incremented by one in step R4, i.e., the next
sound source module No. 2 is designated, and it is then discriminated whether or not
the value of register D-RG is greater than or equal to 9. If it is less than or equal
to 8, the flow returns to step R2, so that the loop is repeated.
[0094] The value of register B-RG may equal to the value (string number) of string number
designation register a in step R3. This means that the presently-designated sound
source module has already generated the musical tone of the presently-triggered string.
In the next step R6, therefore, the presently-designated sound source module is subjected
to the sound stop process and string number designation register a of the sound source
module control register associated with that sound source module is set with zero,
thereby indicating that the sound source module being not busy (or generating no
musical tone). In the next step R7, the value of sound source number designation register
D-RG or the number of the sound source module which has just stopped generating a
musical tone, is written in sound source module assign register LASTMD. The register
LASTMD is for controlling the assigning the sound source module for tone generation
and is used to start the search for the sound source module for tone generation, whose
number follows the value of LASTMD (i.e., the number of the sound source module previously
assigned for tone generation (see steps R16 and R17) or the one previously having
stopped the tone generation).
[0095] In the first step R8 of the second half of the flow, the value of register LASTMD
is set in register D-RG and a value "1" is written in loop number register E-RG. In
the first three steps R9 to R11 of the loop (steps R9-R15), the number of the next
sound source module to be checked is computed and the computation result is written
in register D-RG. In step R12, the content of string number designation register a
of the control register of the that sound source module is loaded, and in next step
R13, it is discriminated whether or not the content of register a is zero, i.e., whether
or not the sound source module under examination is presently generating a musical
tone (or is presently used). If the module is generating the musical tone, the value
of register E-RG is incremented by one. Then, in step R15, it is discriminated whether
or not the value of register E-RG is less than or equal to 8, and if it is less than
or equal to 8, the flow returns to step 9 so as to repeat the loop. If the value of
register E-RG is greater than or equal to 9 in step R15, however, it means that all
of the eight sound source modules are in use. Logically, this event does not occur
and it indicates that a memory is damaged by external factors, so that the proper
error process is executed in step R18.
[0096] If it is discriminated in step R13 that the sound source module under examination
is not generating a musical tone, the flow advances to step R16 where this sound source
module (the one corresponding to the value of register D-RG) is requested to start
generating a musical tone with the pitch determined by the pitch data of the musical
tone of the presently-triggered string, which is the content of pitch designation
register P-RG. At the same time, the value of register B-RG or the number of the presently-triggered
string is written in string number designation register a of the control register
of that sound source module, the value of register C-RG or the pitch data of the presently-generated
musical tone is written in pitch data designation register b, and a predetermine
value (sounding time data) is written in sounding time control counter c. Finally,
in step R17, the value of register D-RG or the number of the sound source module which
has just undergone the ON process (step R16), is written in sound source module assign
register LASTMD.
[Review of Tone Reverberation]
[0097] By now the third feature of the present embodiment, namely, the tone reverberation
function, should be understood; that is, when the same string 4 is stroked successively
while the reverberation of the musical tone generated by the previous string triggering,
the generation of the musical tone originating from the succeeding string triggering
starts.
[0098] For instance, when one string 4 is triggered for the first time, the string triggering
is detected through the flow of the triggering detection process as shown in Fig.
14, and a predetermined sound source module is assigned to generate the associated
musical tone at the second half (steps R8-R18) of the flow of the sound source assigning/sound
generating process (step P7 of Fig. 14 and Fig. 17) and it is memorized that this
sound source module is generating the musical tone associated with the triggered string.
[0099] When the same string 4 is triggered again under such a circumstance, this triggering
of the specific string 4 is also detected. This time, however, the first half of the
flow of the sound source assigning/sound generating process (Fig. 17) does not go
through the ordinary sequence; it is confirmed in step R3 that the generation of the
musical tone associated with the presently-triggered string has "already" been done
by a specific sound source module in musical tone generating circuit 60 (Fig. 4)
and this sound source module is subjected to the sound stop process (step R6). In
the second half of the flow, a new sound source module is assigned to newly generate
the musical tone associated with the presently-triggered string and this new module
is subjected to the sound stop process (step R16).
[0100] Here, the sound source module which is to stop the tone generation generally differs
from the one which is to start the tone generation. Particularly, in the flow of Fig.
17, searching for the sound source module to newly generate a musical tone starts
from the one following the module which has undergone the OFF (sound stop) process
in step R6 and the first unused (a=0) sound source module found is used to generate
the musical tone associated with the newly-triggered string. In other words, the
new sound source module can certainly be found before the search reaches the sound
source module which has undergone the sound stop process (see the operation of register
LASTMD). In the case of very exceptional string operation (e.g., all the strings being
stroked at a very high speed), however, the sound source module which has undergone
the OFF (sound stop) process to provide the tone reverberation will be immediately
selected as a new sound source module in order to perform the tone assignment of the
sequence of the string triggering. Practically, however, this does not cause any problem.
The processes shown in Figs. 14 and 17 are designed to optimally select a different
sound source module to be subjected to the ON process from the one which has undergone
the OFF process, when the same string is stroked successively under the condition
of the restricted number of sound source modules.
[0101] In short, according to this embodiment, when, during generation of a musical tone
originating from the triggering of one string, the same string is triggered again,
the sound source module which is generating the musical tone associated with the string
is caused to stop the tone generation and a different sound source module is assigned
to generate the new musical tone in response to the new triggering of the string.
Accordingly, the tone reverberation function as described with reference to Fig.
8 can be realized.
[0102] As a modification, two (or more) sound source modules may be assigned to each string,
so that at the first string triggering, one of the two sound source modules is subjected
to the ON process, and at the time of the second string triggering, this module is
subjected to the OFF process and the remaining module is subjected to the ON process.
[0103] Further, tone generation assignment to the sound source module which has undergone
the OFF process may be inhibited until this module completely stops the tone generation.
In this case, however, the number of assignable sound source modules is reduced by
this inhibition, thus requiring a large number of sound source modules in total.
[0104] When the timbre is of the release tone system such as guitar sounds, the OFF process
executed in step R6 of Fig. 17 may be eliminated. With instruments using both the
release tone system and sustain tone system, additional discrimination step may be
provided following discrimination step R3 in Fig. 17 to discriminate whether the release
tone system or the sustain tone system is involved, and if it is the sustain tone
system, the OFF process in step R6 is executed and if it is the release tone system,
then the OFF process may be omitted.
Sounding Time Control Process (Figs. 18 and 19)
[0105] As described above, when string triggering occurs, it is detected by microcomputer
30 (Fig. 4), and through the flow of sound source assigning/sound generating process
shown in Fig. 17, an unused sound source module is found from all the sound source
modules of musical tone generating circuit 60 (Fig. 4) in order to generate the musical
tone associated with the triggered string and this module is subjected to the ON process
in step R16. And, the sounding time data is written in sounding time control counter
c (Fig. 16) of the control register of that module in step R16.
[0106] In this embodiment, the sounding time data is determined for each timbre, and when
a timbre is designated by timbre select switch 5a (Fig. 1), the sounding time data
representing the length of time which corresponds to the selected timbre is set in
register ONTIME (see Fig. 18; its detailed explanation will be given later). That
is, it is the sounding time data determined by the presently-selected timbre which
is to be set in sounding time control counter c in step R16 (ON process) in the flowchart
shown in Fig. 17. Microcomputer 30 performs a decrement operation on the sounding
time data set in counter c for each execution of the interrupt routine (the flow of
the timed-out stop sound process as shown in Fig. 19), which puts an interrupt for
each predetermined time interval. And, when the underflow of sounding time control
counter c occurs, microcomputer 30 causes the associated sound source module to stop
the tone generation.
[0107] The sounding time control process will now be explained in detail. Fig. 18 illustrates
a detailed flowchart of the timbre designation change process which is part of panel
switch status change process executed in step G8 of Fig. 5. First, it is discriminated
in step S1 whether or not a new timbre is designated by timbre select switches 5a
(Fig. 1). If no timbre designation is made, other processes are performed in step
S2, but if the new timbre designation is made, the flow advances to step S3 where
timbre data associated with the designation is set. Further, sounding time data corresponding
to the designation timbre is saved in sounding time data save register ONTIME.
[0108] Fig. 19 is a detailed flowchart of the timed-out sound stop process, and microcomputer
30 executes the illustrated interrupt routine for a predetermined time interval. First,
data saving in a register, etc. is executed in step T1 as per an ordinary interrupt
routine. The value of sound source number designation register D-RG, which indicates
the number of the sound source module, is initialized to be 1 in step T2, and thereafter
the loop T3 to T9 is executed.
[0109] In the first step T3 of the loop, the content of string number designation register
a of the sound source module to be checked is loaded (when a=0, the sound source module
is presently unused, and when a=0, the a-th string is generating a musical tone).
In the subsequent step T4, it is discriminated whether or not a=0, i.e., whether
or not the sound source module is presently generating a musical tone. If the musical
tone is being generated, sounding time control counter c for controlling the sound
source module is down-counted in step T5. If a borrow from this counter is detected
in step T6, the flow advances to step T7 where the sound source module is subjected
to the stop sound process (OFF process), and the content of string number designation
register a is set to zero to memorize that the sound source module is no longer generating
a musical tone. After step T7 or when it is discriminated in step T4 that no musical
tone is presently being generated, or when no borrow is detected in step T6, the flow
advances to step T8 where the value of sound source number designation register D-RG
is incremented by one. Then, in the subsequent step T9, it is discriminated whether
or not the value of register D-RG is less than or equal to 8, and if the value is
less than or equal to 8, the flow returns to step T3 to thereby repeat the loop.
[0110] After the loop is completed, data is restored in registers, etc. (step T10), as is
the case where the interrupt process is completed.
[0111] With the above explanation, it should be understood that the fourth feature of this
embodiment, namely, the function for automatically causing the sound source module
to stop the tone generation upon elapse of the sounding time, is realized. The aforementioned
sounding time data is prepared separately from the envelope data included in the timbre
data, so that even during generation of the musical tone envelope or even during
generation of the musical tone from the sound source module in accordance with the
musical tone envelope data, when the time determined by the sounding time data elapses,
the sound source module is requested to stop the tone generation from that instance.
[0112] As a modification, the sounding time data may be designed to be freely programmable
(variable) by a user, thus providing timbres of different impressions.
Fret Status Change Process (Figs. 20 and 21)
[0113] The following explains the fret status change process performed by microcomputer
30 (Fig. 4) in step G5 of the general flow (Fig. 5).
[0114] Fig. 20 is a detailed flowchart of the fret status change process. Microcomputer
30 initializes string number designation register B-RG to have a value 1 in the first
step U1 of the flowchart, and thereafter repeatedly executes the loop U2 to U6.
[0115] In the first step U2 of the loop, it is determined whether or not there is a fret
change. This discrimination is done by comparing the previous sampled values of the
fret switches belonging to the string indicated by the value of string number designation
register B-RG with the present sampled values. The fret change includes a change
from one depressed-string operated status to the so-called open-string (open-fret)
operated status. If a fret change is detected in step U2, the pitch data associated
with the changed fret position is written in pitch designation register C-RG in step
U3. In the subsequent step U4, a frequency change process (Fig. 21; its detailed description
will be given later) using both of the values of the aforementioned string number
designation register B-RG and pitch designation register C-RG. If no fret change is
discriminated in step U2, or after the frequency change process performed in step
U4, the value of string number designation register B-RG is incremented by one to
increase the string number by one in step U5. In the subsequent step U6, it is discriminated
whether the value of register B-RG is less than or equal to 6, and while the value
is less than or equal to 6, the loop starting from step U2 is repeated.
[0116] When the process for the fret change with respect to all the strings is completed,
the value of register B-RG is determined to be 7 in step U6, thus leaving the flow
of the fret status change process.
[0117] Fig. 21 is a detailed flowchart of the aforementioned frequency change process.
At the time the flow starts, the pitch data of a changed fret is held in pitch designation
register C-RG and a value (string number) indicating on which string the fret change
occurred is held in string number designation register B-RG.
[0118] In step V1, the content of sound source number designation register D-RG is initialized
to be 1. Then, the value (string number) of string number designation register a of
the sound source module control register (Fig. 16) indicated by the value of register
D-RG is loaded in step V2, and it is then discriminated in step V3 whether or not
the loaded value of register a equals the value of string number designation register
B-RG. That is, it is checked in step V3 whether or not the musical tone associated
with the string whose fret position has changed is being generated. If the decision
in this step is a non-coincidence, the flow advances to step V10 where the value
of sound source number register D-RG is incremented by one to increase the number
of the sound source module to be checked by one, and then advances to step V11 where
it is discriminated whether or not the value of sound source number designation register
D-RG is less than or equal to 8. If the value is less than or equal to 8, the flow
returns to step V2 to thereby repeat the loop; if the value equals 9, the process
is completed.
[0119] The value of register D-RG becomes 9 in step V11, thus completing the process, when
a fret change occurs on the fret of the string associated with that musical tone which
is undergoing the sound stop process. In such a fret change operation, the fret change
is considered to be invalid so that no musical tone processing is performed.
[0120] When a fret change occurs with respect to the string associated with the presently-generated
musical tone, there exists the sound source module which is generating the musical
tone and this is stored in string number designation register a of the associated
sound source module control register (see Figs. 14 and 17). Therefore, when the value
of register D-RG indicates a sound source module number, the value of register a =
the value of string number designation register B-RG is satisfied in step V3.
[0121] If it is discriminated in step V3 that the musical tone associated with the string
whose fret position has changed is presently being generated, the flow advances to
step V4 where it is discriminated whether or not the fret status is changed to the
open-string operated status by checking the value of pitch designation register C-RG.
If the fret status is not changed to the open-string operated status (i.e., a different
fret being depressed), the flow advances to step V9 where the sound source module,
presently generating the musical tone associated with the string, (this module being
determined by the value of sound source number designation register D-RG) is subjected
to the frequency change process so as to change the frequency of the musical tone
to the one corresponding to the pitch data indicated by the value of pitch designation
register C-RG, and the value of register C-RG is written in pitch designation register
b. In step V9, only frequency change is done as tone processing; stopping the tone
generation, generating a new musical tone or the like is not performed at all. As
a result, the presently-generated musical tone has its frequency change to the one
corresponding to the changed fret position without generating a new musical tone (see
Fig. 7).
[0122] If it is discriminated in step V4 that the fret status is changed to the open-string
operated status, the flow advances to step V5 where it is discriminated whether or
not the value of a string release OFF process execute flag OFFFG is 1 (set). If the
value is 1, the OFF process is executed in step V8. More specifically, the sound source
module which is presently generating the musical tone associated with the string is
subjected to the sound stop process and string number designation register a of the
control register for that module is written with zero which indicates that the module
is unused.
[0123] If the value of flag OFFFG is determined to be 0 (reset) in step V5, the value of
pitch designation register b is loaded in step V6. Here, the value of register b corresponds
to the pitch for the fret status immediately before the occurrence of the fret change.
In subsequent step V7, it is discriminated whether the pitch data immediately before
the occurrence of the fret change corresponded to the first fret position or the second
fret position. If the decision is affirmative, the frequency is changed in step V9,
thus completing the frequency change process. Step V7 is provided in this embodiment
to mainly cope with the sliding of the same string. When the fret status is changed
to the open-string status after the third fret, therefore, it is assumed that a performer
moves the string-pressing fingers onto strings to press them for playing a melody
using a plurality of strings.
[0124] The flap OFFFG indicated in step V5 of Fig. 21 is used to realize the string release
mode select function which is the sixth feature of this embodiment. Accordingly,
this function can be controlled by string release mode select switch 5c (Figs. 1 and
22A) provided in the instrument's main body.
[0125] Fig. 22B illustrates the flowchart for switching the flag OFFFG with respect to the
input of string release mode select switch 5c. This flow is part of the panel switch
status change process executed in step G8 of the general flow of Fig. 5.
[0126] First, it is discriminated in step W1 whether or not string release mode select switch
5c is depressed. If the decision is negative, the flow advances to step W2 for executing
other processes. If the decision is affirmative, it is discriminated in step W3 whether
the string release sound stop mode is ON or OFF. If the mode is ON, flag OFFFG is
set to 1 in step W4, and if it is OFF, the flag OFFFG is set to 0. When flag OFFFG
is set to 1, the presently-generated musical is rapidly released (step V8 in Fig.
21). On the other hand, when flag OFFFG is set to 0, the pitch of the presently-generated
musical tone is changed to that of the open string (step V9 in Fig. 21).
[Review of Open String Sound Stop And Frequency Change Functions]
[0127] With the above explanation, it should be understood that the second feature or the
frequency change function (see Fig. 7) for changing the frequency of a musical tone
without generating a new musical tone and the fifth feature or the string-based sound
stop function (see Fig. 10) resulting from a change to the open-string operated status
are both realized by this embodiment.
[0128] To begin with, the frequency change function as the second feature of this embodiment
will be described. In the sound source assigning/sound generating process (see Figs.
14 and 17), microcomputer 30 assigns a sound source module to generates a musical
tone with a predetermined pitch and writes sound source control data into sound source
control registers a, b and c (Fig. 16). The control data includes data as to which
string's musical tone the sound source module is generating and data as to at what
pitch the musical tone is generated. When the fret operation status is moved to a
different fret position of the string during generation of the musical tone of the
specific string, microcomputer 30 detects the change (as to on which fret position
of which string the fret operation status is changed) through the process shown in
Fig. 20, and searches for the sound source module that is generating the musical tone
of the string and causes the found sound source module to undergo the frequency change
process for changing only the frequency of the presently-generated musical tone through
the process as shown in Fig. 21. Therefore, the function described with reference
to Fig. 7 is certainly realized.
[0129] The frequency change function of this embodiment is performed in response to a change
in the fret operation position of the same string as is presently-generating a musical
tone. In other words, this function is executed when fingering is applied to a single
string. For instance, performance similar to the sliding performed with an acoustic
guitar, etc. or the fingering for a quick phrase with respect to the same string (in
either case, the picking being done only once at the beginning) may be utilized to
provide the same musical effect as can be attained by the mentioned sliding or fingering.
[0130] With regard to the fifth feature of this embodiment or the open string sound stop
function due to a change to the open-string operated status, microcomputer 30 causes
pitch designation register C-RG and string number designation register B-RG to memorize
that the fret position of the presently-generated musical tone is changed to the open-string
operated status, through the process as shown in Fig. 20. Through the process as shown
in Fig. 21, microcomputer 30 then finds the sound source module that is presently
generating a musical tone and confirms that the fret status is changed to the open-string
operated status by checking the value of register C-RG. In this case, the found sound
source module is subjected to the sound stop process as long as flag OFFFG is set.
[0131] From the above, it is obvious that the string-based sound stop function due to the
transition to the open-string operated status as described with reference to Fig.
10 is indeed realized. The string-based sound stop function of this embodiment is
particularly advantageous under the circumstance where the condition for the note
off cannot easily be attained by switches such as string triggering switches TSW (Fig.
3). A performer can freely control the sounding time of the musical tone of a triggered
string by moving his or her fingers off the string at a desired timing. In addition,
this sound stop function is suitable for playing a melody, sequentially using a plurality
of strings. It is further advantageous that no extra switches are needed for the note
off process.
[0132] Further, according to this embodiment, the switching function is provided which
can give higher priority to the frequency change function suitable for the sliding
than the open string sound stop function. Specifically, string release mode select
switch 5c is provided in the instrument's main body to provide easier performing facility
to a performer.
Mute Switch Process (Figs. 22 and 24)
[0133] The following explains the mute switch process (Fig. 23) which is performed by microcomputer
30 (Fig. 4) as part of the panel switch status change process (step G8) of the general
flow (Fig. 5).
[0134] When mute switch 5b (Fig. 1) provided in the instrument's main body is depressed,
the mute function, which is the eighth feature of this embodiment, a requests all
the sound source modules that are generating musical tones at that time to simultaneously
and rapidly stop the tone generation.
[0135] More specifically, in the first step X1 of the flow shown in Fig. 23, microcomputer
discriminates whether or not mute switch 5b is depressed. If the decision is negative,
other panel switch status change processes indicated by step X2 are executed; if it
is affirmative, the entire sound source stop sound process is performed in step X3.
[0136] This sound stop process is illustrated in detail in Fig. 24. A value "1" is set in
sound source number register D-RG to initialize the sound source module number in
the first step Y1, and thereafter, the loop of Y2-Y7 is performed with respect to
the sound source module indicated by the value of register D-RG.
[0137] In the first step Y2 of the loop, of the contents of the registers (sound source
control registers shown in Fig. 16) for controlling the sound source module specified
by the value of register D-RG, the value (string number) of string number designation
register a is loaded. As described earlier, when the value of register a is zero,
it indicates that the associated sound source module is not presently used or is not
presently generating a musical tone, and when the value is other than zero, the musical
tone associated with the loaded value is being generated from the associated sound
source module. In the subsequent step Y3, it is discriminated whether or not the
presently-designated sound source module is generating a musical tone. If the tone
is being generated, the rapid sound stop process is performed with respect to the
sound source module (specified by the value of register D-RG) in step Y4, and zero
is written in string number designation register a of the sound source module in the
next step Y5, thereby memorizing that this sound source module is unused. After step
Y5 or when it is discriminated in step Y3 that the presently-designated sound source
module is not generating a musical tone, the value of register D-RG is incremented
by one in step Y6 to search the next sound source module other than the presently-designated
module. In the subsequent step Y7, it is discriminated whether the value of register
D-RG is less than or equal to 8 so as to determined the completion of the rapid sound
stop process with respect to all of the eight sound source modules included in musical
tone generating circuit 60 (Fig. 4). If the value of register D-RG is less than or
equal to 8, it means that there still remains unchecked sound source modules, so that
the loop starting from step Y2 is repeated. If this value becomes 9, it means that
all the sound source modules have been checked and the rapid sound stop process is
completed.
[0138] With the above explanation, it should be clear that the mute function described with
reference to Fig. 11 is realized. Unlike the ordinary OFF process, the rapid sound
stop process rapidly releases a musical tone.
[0139] This mute function ensures the cutting performed with an acoustic guitar, etc.
[0140] According to this embodiment, in response to the operation of a single mute switch
5b, all of the presently-generated musical tones are rapidly released; however, other
modifications may be possible. For instance, a plurality of mute switches may be provided,
and the rapid sound stop process need not be performed with respect to all of the
strings presently generating musical tones but it may be performed separately with
respect to the musical tone or tones associated with a single selected string or a
plurality of selected strings (to be accurate, those sound sources which are generating
the musical tones of these strings).
[0141] The entire string sound stop function as the sixth feature and the mute reserve function
as the ninth feature will now be explained referring to Figs. 25 to 28.
[0142] Six registers f₁ to f₆ shown in Fig. 25 are used for fret-oriented processes and
are respectively provided for first to sixth strings. Each register f
i has an 8-bit structure, and F7 bit indicates the fret position data (fret number)
of the associated string. All the F7 bits being "0" indicates the open string status.
The most significant bit (MSB) indicates whether or not the fret status is changed,
and the MSB being logical "1" indicates the occurrence of the change.
[0143] Microcomputer 30 sets these registers f₁ to f₆ in step G3 of the general flow (Fig.
4) and checks the MSB of each register f
i in step G4. If any MSB is logical "1," which means that there is a fret status change,
the flow advances to step G5 to perform the fret status change process.
[0144] Through this fret status change process, microcomputer 30 realizes various functions
including the aforementioned full string sound stop function and the string-based
sound stop function.
[0145] Fig. 26 is a detailed illustration of the frets status change process.
[0146] In the first step U1, microcomputer 30 refers to the F7 bits of registers f1-f6 to
discriminate if all the frets are open. When the F7 bits of registers f1-f6 are all
zeros, the fret status is the full open-string operated status. Systematically, the
decision in step U1 indicates the full open-string operated status when any one or
more of the first to sixth strings is depressed and the string-depressing fingers
are then released off all the depressed strings. At this time, some strings (to be
accurate, internal sound sources assigned to these strings) may be or may not be generating
musical tones. It is possible to check which string is generating its musical tone
through the same procedures as described in the sound source assigning/sound generating
process. In brief, string number designation register a which indicates the status
of each sound source module exemplified in Fig. 16 should only be referred to, and
if its value is not zero, the associated string is "generating a musical tone." The
full tone stop process executed in step U2 in the case of the full open-string operated
status is basically preformed in the same manner as has just been explained. All the
sound source modules which are "generating musical tones" are given with a sound stop
request, and their associated, string number designation registers a are all reset
to be zeros to indicate that all sound source modules are unused. (The sound stop
request may be sent to all the sound source modules without referring to registers
a. Those modules which are not generating musical tones simply become NOP.) Anyway,
in response to the full-source sound stop request, every tone-generating sound sources
enters the release mode and releases the generated musical tone. As a result, the
simultaneous tone off can be sensed.
[0147] When any fret is depressed, a value of "1" is written in string number designation
register B-RG in step U3 and the loop of steps U4-U8 is thereafter repeated.
[0148] In the first step U4 of the loop, it is discriminated whether or not a fret change
exists. This discrimination can be done by loading the content of that register f
B-RG which is indicated by the value of register B-RG and checking its MSB. If the change
exists, the fret number data located in the lower 7 bits of the register f
B-RG is written in pitch designation register C-RG in step U5. In the subsequent step
U6, a frequency change process (Fig. 27; its detailed description will be given later)
using both of the values of the aforementioned string number designation register
B-RG and pitch designation register C-RG. If no fret change is discriminated in step
U4, or after the frequency change process performed in step U6, the value of string
number designation register B-RG is incremented by one to increase the string number
by one in step U7. In the subsequent step U8, it is discriminated whether the value
of register B-RG is less than or equal to 6, and while the value is less than or equal
to 6, the loop starting from step U4 is repeated.
[0149] When the process for the fret change with respect to all the strings is completed,
the value of register B-RG is determined to be 7 in step U7, thus leaving the flow
of the fret status change process.
[0150] Fig. 27 is a detailed flowchart of the aforementioned frequency change process.
At the time the flow starts, the position data of a changed fret is held in pitch
designation register C-RG and a value (string number) indicating on which string the
fret change occurred is held in string number designation register B-RG.
[0151] In step V1, the content of sound source number designation register D-RG is initialized
to be 1. Then, the value (string number) of string number designation register a
of the sound source module control register (Fig. 16) indicated by the value of register
D-RG is loaded in step V2, and it is then discriminated in step V3 whether or not
the loaded value of register a equals the value of string number designation register
B-RG. That is, it is checked in step V3 whether or not the musical tone associated
with the string whose fret position has changed is being generated. If the decision
in this step is a non-coincidence, the flow advances to step V9 where the value of
sound source number register D-RG is incremented by one to increase the number of
the sound source module to be checked by one, and then advances to step V10 where
it is discriminated whether or not the value of sound source number designation register
D-RG is less than or equal to 8. If the value is less than or equal to 8, the flow
returns to step V2 to thereby repeat the loop; if the value equals 9, the process
is completed.
[0152] The value of register D-RG becomes 9 in step V10, thus completing the process, when
a fret change occurs on the fret of the string associated with that musical tone which
is undergoing the sound stop process. In such a fret change operation, the fret change
is considered to be invalid so that no musical tone processing is performed.
[0153] When a fret change occurs with respect to the string associated with the presently-generated
musical tone, there exists the sound source module which is generating the musical
tone and this is stored in string number designation register a of the associated
sound source module control register. Therefore, when the value of register D-RG indicates
a sound source module number, the value of register a = the value of string number
designation register B-RG is satisfied in step V3.
[0154] If it is discriminated in step V3 that the musical tone associated with the string
whose fret position has changed is presently being generated, the flow advances to
step V4 where it is discriminated whether or not the fret status is changed to the
open-string operated status by checking the value of pitch designation register C-RG
(fret status register). If the fret status is not changed to the open-string operated
status (i.e., a different fret being depressed), the flow advances to step V5 where
frequency (pitch) data is calculated from the fret number data of the F7 bit of register
C-RG, which indicates the fret position, and the string number data, which is the
value of register B-RG and the frequency data is written in register b. In step 6,
the frequency change process is executed so that the frequency of the musical tone
from the sound source module corresponding to the value of register D-RG is changed
on the basis of the frequency data written in register b. Consequently, only the frequency
of the musical tone is changed without generating a new musical tone.
[0155] If it is discriminated in step V4 that the fret status is changed to the open=string
operated status (i.e., when the F7 bits of pitch designation registers C-RG are all
zeros), the flow advances to step V7 where register a is reset to zero. In the subsequent
step V8, the sound source module associated with the value of register D-RG stops
the tone generation. This sound stop is executed string by string. That is, provided
that the musical tone of that string is being generated or provided that the sound
source for generating the musical tone of the string is assigned by the sound source
assigning/sound generating process and starts the tone generation, this sound stop
request is made to the sound source (which dynamically corresponds to each string)
when the fret status of a specific string is changed to the open-string operated status.
In this manner, the musical tone is stopped for each string.
Mute Reserve Function (Fig. 28)
[0156] As described earlier, mute reserve switch MSW is provided on the body of the electronic
stringed instrument of this embodiment. A performer can operate this mute reserve
switch MSW any time during performance to reserve the muting. A change in mute reserve
switch MSW is detected in step G7 of the general flow (Fig. 4) and a mute flag is
set in step G8 to a value indicating the "muting effect ON."
[0157] Further, as described above, when string triggering occurs, it is detected by microcomputer
30 (Fig. 4), and through the flow of sound source assigning/sound generating process
shown in Fig. 17, an unused sound source module is found from all the sound source
modules of musical tone generating circuit 60 (Fig. 4) in order to generate the musical
tone associated with the triggered string and this module is subjected to the ON process
in step R16. And, the sounding time data is written in sounding time control counter
c (Fig. 16) of the control register of that module in step R16.
[0158] Microcomputer 30 performs a decrement operation on the sounding time data set in
counter c for each execution of the interrupt routine (the flow of the muting process
as shown in Fig. 28), which puts an interrupt for each predetermined time interval.
And, when the underflow of sounding time control counter c occurs, microcomputer 30
causes the associated sound source module to stop the tone generation.
[0159] The mute reserve function will be explained below along the flowchart of Fig. 28.
First, data saving in a register, etc. is executed in step T1 as per an ordinary
interrupt routine. The value of sound source number designation register D-RG, which
indicates the number of the sound source module, is initialized to be 1 in step T2,
and thereafter the loop T3 to T9 is executed.
[0160] In the first step T3 of the loop, the content of string number designation register
a of the sound source module to be checked is loaded (when a=0, the sound source module
is presently unused, and when a=0, the a-th string is generating a musical tone).
In the subsequent step T4, it is discriminated whether or not a=0, i.e., whether
or not the sound source module is presently generating a musical tone. If the musical
tone is being generated, sounding time control counter c for controlling the sound
source module is down-counted in step T5. If a borrow from this counter is detected
in step T6, the flow advances to step T7 where it is determined whether or not the
muting effect is rendered ON, i.e., whether or not the muting is reserved by operation
of mute reserve switch MSW. If the muting is reserved, the flow advances to step T8
where the sound source module is subjected to the rapid sound stop process and the
content of string number designation register a is set to zero to memorize that the
sound source module is no longer generating a musical tone. After step T8 or when
the decisions in steps T4, T6 and T7 are negative, the flow advances to step T9 where
the value of sound source number designation register D-RG is incremented by one.
Then, in the subsequent step T10, it is discriminated whether or not the value of
register D-RG is less than or equal to 8, and if the value is less than or equal to
8, the flow returns to step T3 to thereby repeat the loop.
[0161] After the loop is completed, data is restored in registers, etc. (step T11), as is
the case where the interrupt process is completed.
[0162] When the muting is reserved, therefore, the musical tone generated by picking string
4 is rapidly released upon elapse of the time measured by the sounding time counter
after the beginning of the tone generation. This can provide the same acoustic effect
as the muting effect attained by an acoustic guitar, etc.
[Modification]
[0163] This invention is not limited to the above particular embodiment, but may be modified
or improved in various manners.
[0164] According to the above-described embodiment, this invention is applied to a string
triggering type of electronic stringed instrument, which has a number of fret switches
FSW provided on fingerboard 8 and has string triggering switches TSW coupled to the
respective strings 4 stretched on body 1. However, application of this invention is
not limited to the above instrument. For instance, this invention is applicable to
an electronic stringed instrument, which has a number of fret switches FSW provided
on fingerboard 8 and has electromagnetic type pickups PSW provided below the respective
strings 4, stretched on body 1, so as to detect the string vibration, as shown in
Fig. 29. This invention can also be applied to the various types of electronic stringed
instruments as explained in the first section of this specification, "Background of
the Invention."
[0165] Further, according to this embodiment, the full string sound stop function causes
all the sound sources generating musical tones to stop the tone generation immediately,
simultaneously and in the same manner, in response to the transition to the full open-string
status. Here, the term "in the same manner" means that the musical tones are released
at the same sound stopping time (release time).
[0166] The musical tones may be released at different release times, not in the same manner.
For instance, in order to provide different release times for the individual strings,
the musical tone of a lower-tone string is release with a longer time than that of
a higher-tone string. This may be realized by selectably switches the release portion
of the envelope in accordance with a variable such as the string number specified
by the value of register B-RG.
[0167] The musical tones may be released at different timing, not simultaneously.
[0168] The musical tones may be released with a delay, not immediately. To be specific,
upon occurrence of a full open-string event, all of the tone-generating strings are
subjected to the sound stop process with some delay. In addition, the delay may be
set to be programmable by a user. Measuring the delay may be realized by counter means
or timer means. If the tone generation is stopped immediately, a performer will have
natural and realistic operational feeling and can easily play staccato.
[0169] Furthermore, the full string sound stop function may be designed inapplicable to
a specific string. For instance, in application utilizing a certain string as a pedal
line, the full string sound stop function is not applicable to the string serving
as the pedal line. Even in this case, the meaning of the full string sound stop is
not lost. The full string sound stop function should affect all of a plurality of
strings (not necessarily all the strings used in an electronic stringed instrument),
and is activated when all of these strings are set in the so-called open-string status
as the necessary condition, thereby causing all of tone-generating strings (or sound
sources) to stop the tone generation.
1. An electronic stringed instrument characterized by comprising:
string triggering data output means (TSW) for detecting vibration of at least
one string (4) stretched on an instrument main body (1, 2) and outputting string triggering
data corresponding to said vibration;
pitch designation data output means (FSW) for detecting a pitch designation
operation state of said string (4) and outputting pitch designation data corresponding
to said pitch designation operation state;
musical tone generating means (60, 70, SP) for generating a musical tone with
a pitch designated by said pitch designation data from said pitch designation data
output means (FSW) in response to said string triggering data from said string triggering
data output means (TSW);
temporary storage means (40) for temporarily storing said string triggering
data from said string triggering data output means (TSW);
string vibration start detection means (30) for sampling contents of said temporary
storage means (40) so as to detect beginning of said vibration of said string (4);
and
initializing means (30) for initializing said temporary storage means (40)
upon elapse of a predetermined time from a point of time at which said beginning of
said vibration of said string (4) is detected by said string vibration start detection
means (30).
2. The electronic stringed instrument according to claim 1, characterized in that
there are a plurality of strings (4), said temporary storage means (40) is provided
for each of said strings (4), and said string vibration start detection means (30)
is scanning means for sequentially sampling contents of said temporary storage means.
3. An electronic stringed instrument characterized by comprising:
string triggering data output means (TSW) for detecting vibration of at least
one string (4) stretched on an instrument main body (1, 2) and outputting string triggering
data corresponding to said vibration;
pitch designation data output means (FSW) for detecting a pitch designation
operation state of said string (4) and outputting pitch designation data corresponding
to said pitch designation operation state;
musical tone generating means (60, 70, SP) for generating a musical tone with
a pitch designated by said pitch designation data from said pitch designation data
output means (FSW) in response to said string triggering data from said string triggering
data output means (TSW); and
pitch changing means (30) for changing said pitch designated by said pitch designation
data from said pitch designation data output means (FSW) to a pitch designated by
a change from said pitch designation operation state of said string (4) to another
pitch designation operation state, without generating a new musical tone, when said
change from said pitch designation operation state to said another pitch designation
operation state is detected by said pitch designation data output means (FSW) while
said musical tone is being generated from said musical tone generating means (60,
70, SP) with said pitch designated by said pitch designation data from said pitch
designation data output means (FSW) in response to said string triggering data from
said string triggering data output means (TSW).
4. An electronic stringed instrument characterized by comprising:
string triggering data output means (TSW) for detecting vibration of at least
one string (4) stretched on an instrument main body (1, 2) and outputting string triggering
data corresponding to said vibration;
pitch designation data output means (FSW) for detecting a pitch designation
operation state of said string (4) and outputting pitch designation data corresponding
to said pitch designation operation state;
a plurality of musical tone generating means (60, 70, SP) for generating a musical
tone with a pitch designated by said pitch designation data from said pitch designation
data output means (FSW) in response to said string triggering data from said string
triggering data output means (TSW);
first sounding instructing means (30) for instructing first musical tone generating
means (60) of said plurality of tone generating means (60, 70, SP) to start generating
said musical tone with a pitch corresponding to said pitch designation data from said
pitch designation data output means (FSW) in response to said string triggering data
from said string triggering data output means (TSW); and
second sounding instructing means (30) for instructing second musical tone
generating means (60) different from said first musical tone generating means (60)
to start generating said musical tone with a pitch corresponding to said pitch designation
data from said pitch designation data output means (FSW), when said string triggering
data is outputted again from the same string triggering data output means (TSW) while
said first musical tone generating means (60) is caused by said first sounding instructing
means (30) to generate said musical tone with a pitch corresponding to said pitch
designation data from said pitch designation data output means (FSW).
5. The electronic stringed instrument according to claim 4, characterized in that
said second sounding instructing means (30) instructs said second musical tone generating
means (60) to start tone generation and instructs said first musical tone generating
means (60) to start tone stopping.
6. An electronic stringed instrument characterized by comprising:
string triggering data output means (TSW) for detecting vibration of at least
one string (4) stretched on an instrument main body (1, 2) and outputting string triggering
data corresponding to said vibration;
pitch designation data output means (FSW) for detecting a pitch designation
operation state of said string (4) and outputting pitch designation data corresponding
to said pitch designation operation state;
musical tone generating means (60, 70, SP) for generating a musical tone with
a pitch designated by said pitch designation data from said pitch designation data
output means (FSW) in response to said string triggering data from said string triggering
data output means (TSW);
sounding start instructing means (30) for instructing said musical tone generating
means (60) to start generating said musical tone with a pitch designated by said pitch
designation data from said pitch designation data output means (FSW) in response to
said string triggering data from said string triggering data output means (TSW); and
sound-stop start instructing means (30) for instructing, when said musical
tone generating means (60) is caused to start generating said musical tone by said
sounding start instructing means (30), said musical tone generating means (60) to
start stopping generation of said generated musical tone upon elapse of a predetermined
time from a point of time at which generation of said musical tone has started.
7. The electronic stringed instrument according to claim 6, characterized in that
said sound-stop start instructing means (30) comprises timbre-based sound-stop start
instructing means (30) for instructing said musical tone generating means (60) to
stop generating said generated musical tone upon elapse of a sounding time corresponding
to a timbre of said musical tone, when said musical tone generating means (60) is
caused to start generating said musical tone by said sounding start instructing means
(30).
8. An electronic stringed instrument characterized by comprising:
string triggering data output means (TSW) for detecting vibration of at least
one string (4) stretched on an instrument main body (1, 2) and outputting string triggering
data corresponding to said vibration;
pitch designation data output means (FSW) for detecting a pitch designation
operation state of said string (4) and outputting pitch designation data corresponding
to said pitch designation operation state;
musical tone generating means (60, 70, SP) for generating a musical tone with
a pitch designated by said pitch designation data from said pitch designation data
output means (FSW) in response to said string triggering data from said string triggering
data output means (TSW); and
string-based sound stop instructing means (30) for instructing said musical
tone generating means (60), when a change from said pitch designation operation state
of said string (4) to an open-string operation state is detected by said pitch designation
data output means (FSW) while said musical tone is being generated from said musical
tone generating means (60, 70, SP) with said pitch designated by said pitch designation
data from said pitch designation data output means (FSW) in response to said string
triggering data from said string triggering data output means (TSW), to individually
start stopping generation of those generated musical tones which correspond to said
open-string operation state detected by said pitch designation data output means (FSW).
9. An electronic stringed instrument characterized by comprising:
string triggering data output means (TSW) for detecting vibration of at least
one string (4) stretched on an instrument main body (1, 2) and outputting string triggering
data corresponding to said vibration;
pitch designation data output means (FSW) for detecting a pitch designation
operation state of said string (4) and outputting pitch designation data corresponding
to said pitch designation operation state;
musical tone generating means (60, 70, SP) for generating a musical tone with
a pitch designated by said pitch designation data from said pitch designation data
output means (FSW) in response to said string triggering data from said string triggering
data output means (TSW); and
full-string sound stop instructing means (30) for instructing said musical tone
generating means (60) to start stopping generation of all of generated musical tones
at a time, when a change from each of a plurality of pitch designation operation states
of said at least one string (4) to an open-string operation state is detected by said
pitch designation data output means (FSW) while said musical tone is being generated
from said musical tone generating means (60, 70, SP) with said pitch designated by
said pitch designation data from said pitch designation data output means (FSW) in
response to said string triggering data from said string triggering data output means
(TSW), to individually start stopping of those generated musical tones which correspond
to said open-string operation state detected by said pitch designation data output
means (FSW).
10. An electronic stringed instrument characterized by comprising:
string triggering data output means (TSW) for detecting vibration of at least
one string (4) stretched on an instrument main body (1, 2) and outputting string triggering
data corresponding to said vibration;
pitch designation data output means (FSW) for detecting a pitch designation
operation state of said string (4) and outputting pitch designation data corresponding
to said pitch designation operation state;
musical tone generating means (60, 70, SP) for generating a musical tone with
a pitch designated by said pitch designation data from said pitch designation data
output means (FSW) in response to said string triggering data from said string triggering
data output means (TSW);
pitch changing means (30) for changing said pitch designated by said pitch designation
data from said pitch designation data output means (FSW) to a pitch designated by
a change from said pitch designation operation state of said string (4) to another
pitch designation operation state, without generating a new musical tone, when said
change from said pitch designation operation state to said another pitch designation
operation state is detected by said pitch designation data output means (FSW) while
said musical tone is being generated from said musical tone generating means (60,
70, SP) with said pitch designated by said pitch designation data from said pitch
designation data output means (FSW) in response to said string triggering data from
said string triggering data output means (TSW);
open-string sound stopping means (30) for instructing said musical tone generating
means (60, 70, SP) to stop generating said generated musical tone when a change from
said pitch designation operation state of said string (4) to an open-string operation
state is detected by said pitch designation data output means (FSW) while said musical
tone is being generated from said musical tone generating means (60, 70, SP);
release string mode select means (5c) provided on said instrument main body
(1, 2); and
function select means (30) for selecting, in a predetermined mode designated
by said release string mode select means (5c), which one of a pitch change by said
pitch changing means (30) and a open-string sound stopping by said open-string sound
stopping means (30) is to be executed by priority, in accordance with a setting state
of said predetermined mode designated by said release string mode select means (5c),
when said change from said pitch designation operation state of said string (4) to
said open-string operation state is detected by said pitch designation data output
means (FSW) while said musical tone is being generated from said musical tone generating
means (60, 70, SP).
11. An electronic stringed instrument characterized by comprising:
string triggering data output means (TSW) for detecting vibration of at least
one string (4) stretched on an instrument main body (1, 2) and outputting string triggering
data corresponding to said vibration;
pitch designation data output means (FSW) for detecting a pitch designation
operation state of said string (4) and outputting pitch designation data corresponding
to said pitch designation operation state;
musical tone generating means (60, 70, SP) for generating a musical tone with
a pitch designated by said pitch designation data from said pitch designation data
output means (FSW) in response to said string triggering data from said string triggering
data output means (TSW);
first mute designation control means (30) for performing such a control as
to instruct said musical tone generating means (60, 70, SP) to stop generation of
said generated musical tone in a normal mode in response to satisfaction of a normal
sound stop condition, while said musical tone is being generated from said musical
tone generating means (60, 70, SP) with said pitch designated by said pitch designation
data from said pitch designation data output means (FSW) in response to said string
triggering data from said string triggering data output means (TSW);
at least one mute instructing means (5b) provided on said instrument main body
(1, 2); and
second mute instruction control means (30) for performing such a control as
to instruct said musical tone generating means (60, 70, SP) to stop generation of
said musical tone being generated by said musical tone generating means (60, 70,
SP) in a different mode from said normal mode in response to a mute operation performed
with respect to said mute instructing means (5b).
12. The electronic stringed instrument according to claim 11, characterized in that
there are a plurality of said string triggering data output means (TSW), there is
one mute instructing means (5b), and said second mute instruction control means (30)
comprises full tone mute control means (30) for controlling said musical tone generating
means (60, 70, SP) to stop generation of all of said musical tones being generated
by said musical tone generating means (60, 70, SP), in response to a mute operation
performed with respect to said mute instructing means (5b).
13. The electronic stringed instrument according to claim 11, characterized in that
said second mute instruction control means (30) comprises rapid mute control means
(30) for controlling said musical tone generating means (60, 70, SP) to stop generation
of said musical tone being generated by said musical tone generating means (60, 70,
SP) at a speed higher than a speed at which generation of said generated musical tone
is stopped by said first mute instruction control means (30).
14. The electronic stringed instrument according to claim 11, characterized in that
a number of said mute instructing means (5b) equals a number of said strings (4) and
each of said mute instructing means (5b) comprises monotone mute control means (30)
for, when a mute operation of any of said mute instructing means (5b) is executed,
performing such a control as to stop generation of only those of said musical tones
being generated by said musical tone generating means (60, 70, SP) which correspond
to said mute-operated mute instructing means (5b), in response to said mute operation.
15. An electronic stringed instrument characterized by comprising:
string triggering data output means (TSW) for detecting vibration of at least
one string (4) stretched on an instrument main body (1, 2) and outputting string triggering
data corresponding to said vibration;
pitch designation data output means (FSW) for detecting a pitch designation
operation state of said string (4) and outputting pitch designation data corresponding
to said pitch designation operation state;
musical tone generating means (60, 70, SP) for generating a musical tone with
a pitch designated by said pitch designation data from said pitch designation data
output means (FSW) in response to said string triggering data from said string triggering
data output means (TSW);
mute reserve means (MSW); and
mute instructing means (30) for, when said musical tone generating means (60,
70, SP) starts generating a musical tone with a mute reserved by said mute reserve
means (MSW), instructing said musical tone generating means (60, 70, SP) to rapidly
stop generating said musical tone upon elapse of a predetermined time from a point
of time at which generation of said musical tone has started.
16. The electronic stringed instrument according to claim 15, characterized in that
said predetermined time can arbitrarily be set.
17. The electronic stringed instrument according to claim 15, characterized in that
said mute reserve means (MSW) is provided either on said instrument main body (1,
2) or outside of said instrument main body (1, 2).