[0001] All the touch sensivity instruments manufactured up until now, irrespective of whatever
operating principle may char acterized them, have one fundamental element in common,
that is to say, each individual key plays thanks to a transducer linked functionally
to it. For example, a piano having 73 keys is provided with 73 transducers, each of
which, in some way, represents artistically the pressure or derived mechanical quantity
that the fingers of the person playing the piano applies on the corresponding key.
Experiments carried out, particularly in regard to the inter-finger relationship on
one and the same hand at the time a piece of music is being played, lead to the following
conclusions:
1) it is practically impossible for a number of fingers on one hand to apply, at the
same moment, pressures that differ so much that the ear is able to detect the diversity;
this is because of the synchronous movement mutual dependence of the fingers on one
and the same hand; a difference in pressure can be applied and detected only when
the fingers operate in succession at any small intervals of time;
2) in consequence of the foregoing it is, therefore, possible to use one transducer
for any number of keys, provided that provision be made for a suitable system for
distinguishing the keys that have been depressed, even in a rapid time succession,
and for giving the relevant information to peripheral structures which interpret the
said data and restore acoustic independence between the said depressed keys.
[0002] The object of the device according to the invention is, therefore, to achieve touch
sensitivity in musical instruments provided with a keyboard, using one single transducer
or one transducer for a number of keys, with a reduction in costs in comparison with
the methods adopted to date, the actual ratio being 1:N wherein N is of a value over
and above 1 related to the same transducer.
[0003] The invention is illustrated on the accoompanying figures, in which:
- Figure 1 depicts the device forming the subject of the invention in a block diagram;
- Figure 2 details one application example for the said device;
- Figure 3 shows, in a lateral view, one of the keys depicted in Figure 2.
with reference to the above listed figures, the blocks shown at 1, 2, 3,....N, represent
N keys of a keyboard related to one and the same transducer T.
[0004] Each of these keys is able to exert a force F
1, F
2, F
3,.... F
N, respectively, that is dependent on the pressure applied on the applicable key by
the person playing the instrument. The said forces are all distributed over a force
collection system shown at C, which transmits, for each force or systen of forces
by which it is contenporaneously stressed, one single force F and this, in turn, goes
and stresses the transducer T. In consequence of this, the transducer T furnishes
a response (generally an electrical signal) in the form of an impulse I. The said
impulse I goes into each and every one of N discriminator blocks shown at D
1, D
2, D
3,....D
N but issues only at the output U
1, U
2, U
3,.... U
N of the block or blocks to which consent to open is given by information synchronous
with the force (or electrical control signal 10a) imparted by the relevant depressed
key. The output of the impulse is just as though there were N transducers, each linked
to one particular key, though independent of one another.
[0005] Three keys, shown at 1, 2 and 3, are depicted in Figure 2, able to rotate around
a pivoting point shown at 6. At 4 are shown the hammers that stress, for example directly,
the transducer T from which, in a time sequence, the impulses I are taken.
[0006] with reference to Figure 3, when the key 1 is depressed it rotates around the pivot
6 and the bammer 4 strikes the transducer T. At the same time as the latter is being
stressed, the support 8 (integral with the key) raises a metal spring, shown at 9,
as far as it will go so that it be brought into contact with an electrical conductor,
shown at 10, from which the electrical control signal 10a is withdrawn. The said signal
(normally a direct current voltage signal) goes into a block shown at 11 (for example
an "AND" circuit) contemporaneously with the impulse I supplied by the transducer
T. The function of the block 11 is that of an electronic switch, that is to say, it
only allows the impulse I to pass when the electrical control signal 10a is also present.
In cases when the electronic switch is provided with a timing system 12 (for example
an ordinary R-C circuit) and thus the control voltage acts only for a suitable period
of time, independently of for how long the relevant key may remain depressed, it can
readily be appreciated that even if other keys belonging to the same group (in other
words related to the same transducer) are depressed, despite the impulses I thus created
being present at the input to the block 11, they are not able to pass through the
output U of the said block since the consent to do this is lacking.
[0007] Obviously the block 11 together with the timing system 12 can constitute one of the
discriminator blocks D depicted in Figure 1.
[0008] In this way a simple system is achieved by which the keys depressed can be discriminated
in the way outlined herein.
1. A device for achieving touch sensitivity in musical instruments provided with a
keyboard, wherein there is one single transducer T for a number of keys in excess
of one, and any mechanical, electronic or electromechanical systen that can succeed
in discriminating the keys depressed among those belonging to a croup related to one
and the same transducer T.
2. A device according to Claim 1, wherein the transducer T is any direct or compound
transducer realized with any direct or derived principle of physics such as, for example,
an electromagnetic transducer, an electrostatic transducer, a piezoelectric transducer,
an optical transducer, a Hall effect transducer, etcetera.
3. A device according to Claims 1 and 2, wherein there are systems for stressing the
transducer T actuyted by the keys both directly and indirectly through the medium
of auxiliary manual, semi-automatic and automatic systems.
