A SEAT ARRANGED FOR ENHANCED SOUND PERCEPTION VIA VIBRATION

Abstract

 According to an example embodiment, a seat arranged for joint production of vibration and sound is provided. The seat comprises vibration means for jointly producing vibration and sound to reproduce an input audio signal provided as input thereto, said vibration means arranged inside a padding of the seat to generate mechanical vibration that is perceivable as a vibration and sound on at least one outer surface of the padding and to radiate a sound through said at least one outer surface of the padding and said vibration means comprising at least one mechanical actuator and at least one board, wherein said at least one mechanical actuator is arranged to vibrate said at least one board in accordance with the input audio signal. The seat further comprises isolation means for mechanically isolating the vibration means from adjacent structures.

Description

TECHNICAL FIELD

[0001] The example embodiments of the present invention relate to a seat that enables enhanced sound perception via vibration.

BACKGROUND

[0002] In movie theaters, accurate sound reproduction sets requirements both for the audio system and the room construction. Usually, a large number of loudspeakers are used to render the spatial /directional properties of sound, whereas subwoofer loudspeakers need to be driven at a high power to achieve strong low frequency effects. There are at least two challenges with existing solutions for movie soundtrack reproduction, as briefly discussed in the following.

[0003] Firstly, in order to provide strong low frequency effects, big loudspeakers that require several kilowatts of power are used to generate sound pressure levels that can be felt as explosions and other effects that are typical in movies of certain genres. However, intense low frequency sounds disturb neighboring spaces as they are able to radiate through walls and/or other heavy structures. In many cases sound pressure levels are excessive also in the higher audible frequencies. Therefore, movie theater buildings and spaces within a movie theater typically need to be built with heavy walls that isolate the sound and vibration transmission.

[0004] Secondly, spatial sound reproduction is not uniform and equal between seat locations within a movie theater. Both the spatial / direction properties of sound and the ambience of the soundscape are typically compromised in seats that are located close to a loudspeaker (e.g. seats at the sides of the movie theater: the sound channel(s) reproduced by the closest loudspeaker(s) are over-emphasized while other sound channels are weaker in relation and may also suffer from delay effects. Especially surround speakers that are located to side walls are prone to create audible artifacts in audience seat locations close to them.

[0005] There are some known solutions for the second challenge, outlined in the following examples.

• Usage of a high number of surround speakers or speaker groups with phase and directivity control (e.g. Dolby Atmos) enables improved spatial control to account different locations of the seats in relation to the employed speakers. This, however, leads to a rather complex sound reproduction system that still involves some non-uniformity of the perceived soundscape between the seat locations.
• Usage of dedicated set of local loudspeakers (for a seat or for a group of seats) to locally create the surround effect. A challenge in such a solution is the localization of the soundscape and it also requires a high number of speakers.
• Usage of headphones for listening enables accurate reproduction of the soundscape. However, a drawback of such solution is that the soundscape turns with the head of the user wearing the headphones, thereby breaking the 'alignment' between the soundscape and the visual content. Moreover, some people may consider usage of headphones inconvenient.

SUMMARY

[0006] Therefore, an object of the present invention is to provide a sound reproduction arrangement that, on one hand, enables provision of strong low frequency effects without causing severe disturbances to adjacent spaces while on the other hand enables faithful reproduction of the spatial / directional component of the soundscape at a reasonable complexity and cost.

[0007] According to an example embodiment, a seat arranged for joint production of vibration and sound is provided, the seat comprising vibration means for jointly producing vibration and sound to reproduce an input audio signal provided as input thereto, said vibration means arranged inside a padding of the seat to generate mechanical vibration that is perceivable as a vibration and sound on at least one outer surface of the padding and to radiate a sound through said at least one outer surface of the padding and said vibration means comprising at least one mechanical actuator and at least one board, wherein said at least one mechanical actuator is arranged to vibrate said at least one board in accordance with the input audio signal, and isolation means for mechanically isolating the vibration means from adjacent structures.

[0008] According to another example embodiment, a method for joint production of vibration and sound in a seat is provided, the method comprising jointly producing vibration and sound to reproduce an input audio signal by using a vibration means arranged inside a padding of the seat to generate mechanical vibration that is perceivable as a vibration and sound on at least one outer surface of the padding and to radiate a sound through said at least one outer surface of the padding, said vibration means comprising at least one mechanical actuator and at least one board, wherein said at least one mechanical actuator is arranged to vibrate said at least one board in accordance with the input audio signal, and mechanically isolating the vibration means from adjacent structures.

[0009] According to another example embodiment, a sound reproduction arrangement is provided, the arrangement comprising a plurality of seats according to an example embodiment described above for reproduction of a respective near-field sound, each of the plurality of seats arranged to receive a first sub-set of audio channels of a multi-channel audio signal; as the input audio signal, and one or more far-field loudspeakers for reproduction of a far-field sound for said plurality of seats, wherein the far-field sound represents a second sub-set of audio channels of said multi-channel audio signal.

[0010] The exemplifying embodiments of the invention presented in this patent application are not to be interpreted to pose limitations to the applicability of the appended claims. The verb "to comprise" and its derivatives are used in this patent application as an open limitation that does not exclude the existence of also unrecited features. The features described hereinafter are mutually freely combinable unless explicitly stated otherwise.

[0011] Some features of the invention are set forth in the appended claims. Aspects of the invention, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of some example embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF FIGURES

[0012] The embodiments of the invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, where

Figure 1 schematically illustrates some components of a seat according to an example embodiment;

Figure 2 schematically illustrates some components of a seat according to an example embodiment;

Figure 3 schematically illustrates some components of a seat according to an example embodiment; and

Figure 4 schematically illustrates some components of a sound production arrangement in a space according to an example embodiment.

DESCRIPTION OF SOME EMBODIMENTS

[0013] Various example embodiments of the present invention relate to a seat that is provided with a vibration assembly for joint production of vibration and sound.

[0014] The seat comprises sound and vibration generating arrangement for jointly producing vibration and sound to reproduce an audio signal provided as input thereto, where the sound and vibration generating arrangement is provided inside a padding of the seat to generate mechanical vibration that is perceivable as a vibration and sound on at least one outer surface of the padding and to radiate a sound through said at least one outer surface of the padding. The sound and vibration generating arrangement comprises at least one mechanical actuator and at least one board, wherein said at least one mechanical actuator is arranged to vibrate said at least one board in accordance with the audio signal provided as input thereto. In this arrangement, the audio signal can be considered to drive the sound and vibration generating arrangement to reproduce the audio signal, and this audio signal is referred to in the following (also) as input audio signal.

[0015] The seat further comprises isolation arrangement for mechanically isolating the sound and vibration generating means from adjacent structures. Mechanical isolation from the adjacent structures, on one hand, enables providing vibration and sound using relatively low energy while on the other hand the mechanical isolation serves to prevent from transferring the vibration to the adjacent structures. These (and other) advantages of the seat according to various example embodiments of the present invention are described in the following by a number of examples.

[0016] The sound and vibration generating arrangement may be also referred to as means for jointly producing vibration and sound to reflect the fact that there is a plurality of ways to implement such an arrangement inside the padding of the seat. Examples in this regard include the approach described in the international patent application published as WO 2015/118217 A1, which is incorporated by reference in its entirety herein. Further examples in this regard are described in the co-pending European patent application no. 16169568.9, which is also incorporated by reference in its entirety herein.

[0017] In the interest of editorial clarity of the description, in the following we predominantly refer to the sound and vibration generating arrangement (e.g. means for jointly producing vibration and sound) as sound reproduction means, as a sound reproduction assembly, as vibration means or as a vibration assembly. Along similar lines, the isolation arrangement is predominantly referred to in the following as isolation means or as an isolation assembly.

[0018] Various examples provided in this text refer to the seat being provides as a seat of a movie theatre. This, however, is a non-limiting example and the seat described herein may be employed in domestic, recreational and professional domains of various types. As a few examples in this regard, the seat may be provided as an armchair for domestic use, as a seat of a vehicle (in a car, in a bus, in a truck, in a train, in an airplane, etc.), as a seat of a public space such as an auditorium, a conference room, etc.

[0019] Throughout this text, references to the audio signal are made. While an audio signal may be considered to consist of frequencies that are audible in view of human hearing system, e.g. approximately from 50 Hz, to 20 kHz, herein the term audio signal is to be construed broadly, encompassing also infrasonic frequencies below the audible frequency range (e.g. down to 5 Hz) and/or ultrasonic frequencies above the audible frequency range (e.g. up to 30 kHz).

[0020] Parallel to hearing system through ears, extended definition of audio signal encompasses also effects to related senses that are affected by the acoustical excitation in the audio frequency range. Sense of touch reacts to vibration both on skin and inner tissues of the human body. Typically cutaneous receptors on skin capture information in the audible frequencies 30 to 500 Hz. If the airborne sound transmitted by fluid (air or water) is intense enough, skin is vibrating and this audiotactile perception supports the auditory perception. Synchronic information from the sense of touch and from hearing support each other, thereby increasing the clarity of the perceived audio information. At lower audiotactile frequencies, say frequencies below 100 Hz, mechanical vibration is easily propagating also to body parts located below skin, and mechanical vibration receptors in joints and muscles react to audio signal. Vibration is further affecting deeper body parts with very low audio frequencies and infrasonic frequencies. Typically frequencies below 30 Hz are not audible by a human listener, and signal components at such frequencies are primarily perceived as body vibration via mechanical contact to the environment. Infrasonic frequencies are typically related to large mechanical events like earthquakes or explosions that vibrate and deform structures and that can be perceived via feet. Skin can also sense infrasound frequencies as pressure sensation, or via various nonlinear mechanisms (e g clothes flapping towards skin).

[0021] Herein, the term tactile frequencies or tactile band is used to refer to a range of frequencies that convey vibration to a human subject but that do not convey (a significant amount of) audible sound to the human subject. The tactile band may cover frequencies approximately from 5 to 30 Hz. The term audiotactile frequencies or audiotactile band is used to refer to a range of frequencies that convey both audible sound and vibration to a human subject. The audiotactile band may cover frequencies approximately from 30 to 500 Hz. The term audio frequencies or audio band is used to refer to a range of frequencies that convey audible sound but that does not convey (a significant amount of) vibration to the human subject. The audiotactile band may cover frequencies approximately from 500 Hz to 20 kHz.

[0022] The limits between the tactile band and the audiotactile band and between the audiotactile band and the audio band typically exhibit some variation from one person to another and hence the figures in this regard provided in the foregoing serve as non-limiting examples. For instance, the upper limit of the tactile band (and hence the lower limit of the audiotactile band) may be a frequency in a range from 20 to 50 Hz, whereas the upper limit of the audiotactile band (and hence the lower limit of the audio band) may be a frequency in a range from 500 to 1000 Hz.

[0023] Figure 1 schematically illustrates some components of a seat 100 according to an example to assist description of various example embodiments of the present invention. In the illustration of Figure 1, the seat 100 is shown with a backrest 102 and a seat part 104 (i.e. the part of seat 100 intended for sitting on) that represent components of a body of the seat 100. Figure 1 further shows a sound reproduction assembly 110, which is elastically coupled to the body of the seat 100, in this example to an upper part of the backrest 102.

[0024] The body of the seat 100, in turn, may be attach to a base (now shown) that includes a rigid or substantially rigid structure for mounting the seat 100 to its environment, e.g. to a floor or to an installation platform arranged on top of the floor. In this the seat 100, the elastic coupling between sound reproduction means 110 and the body of the seat 100 is provided as one or more first springs 106 (having a spring constant k1). Instead of using one or more first springs 106, elastic materials of other type may be employed.

[0025] The characteristics of the elastic coupling between the sound reproduction means 110 and the body of the seat 100 may be selected such that the elastic coupling serves as a (first) isolation arrangement (or isolation means) for mechanically isolating the sound reproduction means 110 from the body so as to prevent from transferring the vibration produced by the sound reproduction means 110 to adjacent structures via the body of the seat 100. In the example of Figure 1 making use of the one or more first springs 106 to implement the elastic coupling, such mechanical isolation may be provided by suitable selection of the spring constant k1. In this regard, the characteristics of the mechanical isolation provided the one or more first springs 106 depend on the resonance frequency of the arrangement formed by the sound reproduction means 110, the one or more first springs 106 and the body of the seat 100: this arrangement provides mechanical isolation only at frequencies above the resonance frequency. Thus, the one or more first springs 106 are selected such that they have sufficiently low spring constant k1 (i.e. low stiffness) to enable mechanical isolation of frequencies in the tactile band and the audiotactile band.

[0026] Further referring to Figure 1, the sound reproduction means 110 may be arranged as part of a neckrest of the seat 100, and hence in this example the at least one board and the mechanical actuator may be arranged inside a padding in the neckrest of the seat 100. As an example, such an arrangement of the at least one mechanical actuator and the at least one board may be provided e.g. by mechanically connecting or suspending a moveable magnet to the at least one board and driving the movement of the moveable magnet by the input audio signal. In a variation of this example, the moveable magnet may be a magnet assembly of a loudspeaker element, which loudspeaker element is mechanically connected to the at least one board.

[0027] Figure 2 schematically illustrates some components of a seat 200 according to an example to assist description of various example embodiments of the present invention. In the illustration of Figure 2, the seat 200 is shown with the backrest 102 and the seat part 104 that represent components of a body of the seat 200. Figure 2 further shows a sound reproduction assembly 110, which is coupled to the body of the seat 200. In this example, the sound reproduction means is coupled to a rigid or substantially rigid board arranged inside a padding of the backrest 102. While also in this example the sound reproduction means 110 is coupled to an upper part of the backrest 102, for seat 200 the coupling to the board inside the padding of the backrest 102 is rigid or essentially rigid, thereby transferring the vibration generated by the sound reproduction means 110 to the backrest 102. Consequently, also the board arranged inside the padding of the backrest 102 serves as a board that is vibrated via operation of the at least one mechanical actuator of the sound reproduction means 110. The board arranged inside the padding of the backrest 102 may extend to the full or substantially full length of the backrest or the board may cover only a part of the full length of the backrest. Nevertheless, due its rigidity the board arranged in the backrest 102 transfers vibration received from the sound reproduction means 110 to a person sitting in the seat 200 via a large contact area, thereby providing enhanced perception of tactile and audiotactile frequencies for improved perception of low frequency content of a soundscape carried in the input audio signal used to drive the sound reproduction means 110. The body of the seat 200, in turn, may be elastically coupled to a base 108 that enables mounting the seat 200 to its environment, e.g. on a floor or on an installation platform arranged on top of the floor.

[0028] In an example, the coupling between sound reproduction means 110 and the body of the seat 200 may be provided by one or more first springs 106 (having a spring constant k2) that result in a relatively rigid coupling between the two elements. As described in the foregoing, the characteristics of the mechanical isolation provided the one or more first springs 106 depend on the resonance frequency of the arrangement formed by the sound reproduction means 110, the one or more first springs 106 and the body of the seat 200, and hence such an arrangement provides mechanical isolation only at frequencies above the resonance frequency, whereas frequencies below the resonance frequency are conveyed from the sound reproduction means 110 to the body of the seat 200 via the one or more first springs 106. Thus, in this case the one or more first springs 106 are selected such that they have spring constant k2 that results in a resonance frequency that enables conveying at least the tactile frequencies and possibly also audiotactile frequencies to the body of the seat 200. In another example, a fixed structure that provides rigid or substantially rigid coupling may be used instead of the one or more first springs 106 to provide rigid or substantially rigid coupling between sound reproduction means 110 and the body of the seat 200. In this case, also higher frequencies are transmitted to the body of the seat 200 via the backrest 102.

[0029] The elastic coupling between body of the seat 200 and the base may be provided as one or more second springs 112 (having a spring constant k3). Instead of using one or more second springs 112, elastic materials of other type may be employed. The characteristics of the elastic coupling between the body of the seat 200 and the base 108 may be selected such that the elastic coupling serves as a (second) isolation arrangement (or isolation means) for mechanically isolating the sound reproduction means 110 from the base 108 so as to prevent from transferring the vibration produced by the sound reproduction means 110 to adjacent structures via the body and base 108 of the seat 200. In the example of Figure 2 making use of the one or more second springs 112 to implement the elastic coupling, such mechanical isolation may be provided by suitable selection of the spring constant k3. Along the lines described in the foregoing, the characteristics of the mechanical isolation provided the one or more second springs 112 depend on the resonance frequency of the arrangement formed by the base 108, the one or more second springs 112 and the body of the seat 200, such that mechanical isolation is provided only at frequencies above the resonance frequency. Thus, the one or more second springs 112 are selected such that they have sufficiently low spring constant k3 (i.e. low stiffness) to enable mechanical isolation of frequencies in the tactile band and in the audiotactile band.

[0030] In addition to coupling the sound reproduction means 110 to the board inside the padding of the backrest 102 in a rigid or essentially rigid manner in the seat 200, the sound reproduction means 110 may be further coupled in a rigid or substantially rigid manner to one or more (rigid or substantially rigid) boards arranged inside a respective part of the padding of the seat 200 in one or more of the following parts of the seat 200: the seat part 102, an armrest of the seat 200, a footrest of the seat 200. The rigid or substantially rigid coupling to one or more further boards may be provided via rigid or substantially rigid coupling between the board arranged inside the padding of the backrest 102 and the respective further board. Such an arrangement further enhances transferring the vibration from the sound reproduction means 110 to a person sitting in the seat 200 via a large contact area for improved perception of low frequency content of a soundscape carried in the input audio signal used to drive the sound reproduction means 110.

[0031] Figure 3 schematically illustrates some components of a seat 300 according to an example to assist description of various example embodiments of the present invention. The seat 300 is a variation of the seat 200 with the elastic coupling between the body of the seat 300 and the base 108 at least partially replaced with active isolation means 114. Hence, in the seat 300 at least some of the one or more second springs 112 of the seat 200 may be replaced with the active isolation means 114. The active isolation means 114 may comprise sensor means for detecting characteristics of vibration transferred from the vibration means 110 to the base 108 and damping means for adaptively cancelling the vibration transferred from the vibration means 110 in accordance with detected characteristics of the vibration transferred from the vibration means 110. Active isolation means 114 may comprise e g. a moving magnet actuator that creates inertial force to the base 108. In another example, the active isolation means 114 may comprise any other inertial or direct actuator arrangement for active vibration cancellation. Additionally or alternatively, the active isolation means 114 may be arranged to detect characteristics of vibration transferred (from the adjacent structure) via the base 108 to the body of the seat 300 and the damping means may be arranged to adaptively cancel the vibration so transferred in order to avoid introducing disturbances in the vibration generated by the sound reproduction means 110 in accordance with input audio signal. The active isolation means 114 may be arranged to (detect and) cancel vibration across in a predefined frequency band or bands. In an example, the active isolation means 114 is arranged to (detect and) cancel vibration in the tactile band and/or in the audiotactile band. In another example, the active isolation means 114 is arranged to (detect and) cancel vibration across the frequency range that covers the tactile band, the audiotactile band and the audio band.

[0032] The seat 100, 200, 300 may further comprise control means that enables a user to separately adjust the intensity (e.g. level or amplitude) of the vibration / sound at least in two frequency bands. As an example, two or more of the following aspects may be adjustable independently of each other:

• intensity of the vibration in a tactile band, e.g. at frequencies approximately from 5 to 50 Hz;
• intensity of the vibration/sound in an audiotactile band, e.g. at frequencies approximately from 50 to 500 (or 1000) Hz;
• intensity of the sound in an audio band, e.g. at frequencies approximately from 500 (or 1000) Hz to 20 kHz.

[0033] Control means that enable such adjustment of vibration/sound intensity may be employed to provide the seat 100, 200, 300 with means for adjusting intensity of the sound radiated through said at least one outer surface of the padding and/or with means for adjusting intensity of the vibration and sound on said at least one outer surface of the padding.

[0034] As described in the foregoing, the sound reproduction means 110, e.g. in accordance with the examples described in context of the seats 100, 200 and 300 in the foregoing, comprises at least one mechanical actuator and at least one board arranged inside the padding of the seat, wherein said at least one mechanical actuator is arranged to vibrate said at least one board in accordance with the input audio signal provided thereto. Exemplifying structures for the sound reproduction means 110 are outlined in context of description of the seat 100 in the foregoing, while different examples of arrangements with respect to the at least one board are described in the foregoing in context of seats 100 and 200.

[0035] In an example, the sound reproduction means 110 comprises a single mechanical actuator and is therefore able to reproduce monophonic sounds. In another example, the sound reproduction means 110 comprises two mechanical actuator or three or more mechanical actuators. Such implementation of the sound reproduction means 110 is therefore further able to reproduce stereophonic input audio signals or two or more channels of a multi-channel input audio signals. However, also scenarios where the sound reproduction means 110 includes a single mechanical actuator for driving production vibration and sound, the advantageous features of effectively conveying the low frequency input audio signal content to a listener via combined effect of audible and tactile sensations at low energy while avoiding transfer of the generated vibrations to the adjacent structures.

[0036] In a scenario where at least two mechanical actuators are available in the sound reproduction means 110, they may be arranged to reproduce a spatial sound that represents at least part of a spatial audio image carried in the input audio signal provided as a multi-channel audio signal. As an example in this regard, the spatial sound may originate or may be derived on basis of one or more rear channels and/or one or more surround channels of a multi-channel audio signal. This aspect will be described in more detail in the following.

[0037] As already discussed in the background section in the foregoing, production of strong low frequency effects e.g. in a movie theatre requires generation of high sound pressure levels using large loudspeakers, which typically causes disturbances to adjacent spaces (e.g. adjacent rooms or adjacent building) via vibrations transferred thereto via floors, walls and/or other fixed structures of the space/building.

[0038] As also already discussed in the background section in the foregoing, spatial sound reproduction e.g. in a movie theatre is not uniform or equal across seats in the room, but especially seats at and close to the sides of the room, where the loudspeakers employed to produce spatial sound components are typically located, suffer from distorted soundscape due to the perceived overemphasis of the sound received from the closest loudspeaker(s) (and, conversely, under-emphasis of the sound received from the furthest loudspeaker(s)).

[0039] Figure 4 schematically illustrates a plan view of a movie theater arrangement provided with a sound reproduction arrangement that comprises 7 loudspeakers arranged to reproduce respective channels of the input audio, including a (front) left channel (L), a center channel (CTR), a (front) right channel (R), a surround left channel (SL), a surround back channel (SB), a surround right channel (SR) and a subwoofer channel (Sub). The loudspeakers for the L, CTR, R, SL, SB, SR and Sub channels are arranged in a space around (four) rows of seats, while the assumed viewing direction is upward in the plan view of Figure 4 (i.e. towards the loudspeakers for the L, CTR and R channels). In this example, the L, CTR and R channels represent front channels and the SL, SB and SR channels represent surround channels. In other examples a different number and/or configuration of front channels and/or a different number/configuration of surround channels may be employed. Herein, the movie theatre serves as a non-limiting example of an environment where the arrangement of seats 100, 200, 300 may employed for improved sound perception. Further examples in this regard include conference rooms, auditoriums, etc.

[0040] In an example, the seats in an arrangement like the one shown in Figure 4 may be replaced e.g. with respective seats 100, 200 or 300 where the sound reproduction means 110 is arranged to reproduce the part of the soundscape represented by the Sub channel. Consequently, the loudspeaker for the Sub channel of the arrangement shown in Figure 4 can be omitted due to the sound reproduction means 110 conveying the respective audio information for each seat 100, 200, 300 separately while the loudspeakers for the remaining channels may be employed as shown in the arrangement of Figure 4. With such an arrangement, the low frequency content of the Sub channel that would otherwise require a high power is now provided a significantly lower power to each of the seats 100, 200, 300 separately, while providing the same or even reinforced perceived effect for a listener/viewer. This, in turn, enables employing more lightweight (and hence typically less expensive) structures in the room/building that hosts the movie theatre since the risk of transferring vibration to adjacent structures (e.g. adjacent rooms or buildings) is avoided or at least significantly reduced.

[0041] Moreover, in the scenario of Figure 4 it is easy to see that the seats towards the left end of the rows are clearly closer to the loudspeaker for the SL channel than the SR channel and vice versa. Therefore, in an example, the seats in an arrangement like the one shown in Figure 4 may be replaced e.g. with respective seats 100, 200 or 300 where the sound reproduction means 110 is provided with at least two mechanical actuators and where the at least two mechanical actuators are arranged to reproduce the part of the soundscape represented by the SL, SB and SR channels together with the sound conveyed in the Sub channel. Consequently, the loudspeakers for these channels of the arrangement shown in Figure 4 can be omitted due to the sound reproduction means 110 conveying the respective audio information for each seat 100, 200, 300 separately while the loudspeakers for the L, CTR and R channels may be employed as shown in the arrangement of Figure 4. Hence, the loudspeakers for the L, CTR and R channels provide far-field sound reproduction that is common for all seats 100, 200, 300, whereas the sound reproduction means 110 in each of the seats 100, 200, 300 serves to provide near-field sound reproduction for each seat 100, 200, 300 separately. The loudspeakers that provide the far-field sound may be referred to as far-field loudspeakers, whereas the sound reproduction in a seat 100, 200, 300 serves as the (dedicated) near-field loudspeaker(s) for that seat 100, 200, 300.

[0042] Such modification of the arrangement of Figure 4 provides at least the following advantages:

• The low frequency content of the Sub channel that would otherwise require a high power is provided a significantly lower power to each of the seats 100, 200, 300 separately, while providing the same or even reinforced perceived effect for a listener/viewer. This, in turn, enables employing more lightweight (and hence typically less expensive) structures in the room/building that hosts the movie theatre since the risk of transferring vibration to adjacent structures (e.g. adjacent rooms or buildings) is avoided or at least significantly reduced.
• The surround component(s) of the soundscape are provided individually for each of the seats 100, 200, 300, thereby reproducing the intended soundscape at increased accuracy especially for the seats 100, 200, 300 that are at or close to the end of a row of seats.

[0043] In a variation of the above example, also the part of the soundscape represented by the L, CTR and R channels is reproduced by the sound reproduction means 110, thereby dispensing with the need to use any loudspeakers for far-field sound reproduction. Also this approach the full soundscape is adequately reproduced, partially due to primary attention of a viewer/listener being directed to visual content provided on the movie screen.

[0044] If making use of the sound reproduction means 110 in a plurality of seats 100, 200, 300 in a movie theatre (or a space/room of another type) for perception of surround sound such that part of the soundscape is conveyed via far-field sound reproduction (e.g. the L, CTR and R channels) while the remaining part is conveyed via near-field sound reproduction for each seat 100, 200, 300 separately (e.g. the SL, SB, SR and Sub channels), it may be advantageous to employ, separately for each of the seats 100, 200, 300 (or separately for each row of seats 100, 200, 300), delay adjustment means for compensating for the propagation delay of the sound via the air from the loudspeakers that serve to reproduce the far-field sound and the seat 100, 200, 300 (or the row of seats 100, 200, 300) to avoid temporal misalignment between the far-field sound and the near-field sound. The delay adjustment for a given seat 100, 200, 300 (or for a given row of seats 100, 200, 300) may comprise delaying reproduction of the near-field sound by an amount that correspond to the propagation delay from the loudspeakers that serve to reproduce the far-field sound to the given seat (or to the given row of seats 100, 200, 300).

[0045] As an example, the delay adjustment means may be provided separately by a dedicated delay adjustment entity provided in each of the seats 100, 200, 300. As another example, the delay adjustment means may be provided centrally, separately from the seats 100, 200, 300, by using a dedicated delay adjustment entity that adjusts the delay for each of the seats 100, 200, 300).

[0046] Additionally, it may be advantageous to provide or enable intensity adjustment means for compensating the possible imbalance between the intensity of the far-field sound and the intensity of near-field sound. As an example, the intensity adjustment means may be provided separately in each of the seats 100, 200, 300 as an intensity control entity that enables adjusting the intensity of the near-field sound provided via the sound reproduction means 110 in the seat 100, 200, 300, thereby enabling the viewer/listener to adjust the near-field sound intensity to match the far-field sound intensity according to his/her preferences.

[0047] In the description in the foregoing, although some functions have been described with reference to certain features, those functions may be performable by other features whether described or not. Although features have been described with reference to certain embodiments or examples, those features may also be present in other embodiments or examples whether described or not.

Claims

1. A seat arranged for joint production of vibration and sound, the seat comprising
vibration means for jointly producing vibration and sound to reproduce an input audio signal provided as input thereto, said vibration means arranged inside a padding of the seat to generate mechanical vibration that is perceivable as a vibration and sound on at least one outer surface of the padding and to radiate a sound through said at least one outer surface of the padding and said vibration means comprising at least one mechanical actuator and at least one board, wherein said at least one mechanical actuator is arranged to vibrate said at least one board in accordance with the input audio signal, and
isolation means for mechanically isolating the vibration means from adjacent structures.

2. A seat according to claim 1, wherein said at least board comprises at least one rigid or substantially rigid board arranged in one or more of the following:

a backrest of the seat,

a seat part of the seat;

an armrest of the seat,

a footrest of the seat,

a headrest of the seat.

3. A seat according to claim 1 or 2, wherein said at least one mechanical actuator comprises at least two mechanical actuators for reproducing a spatial sound.

4. A seat according to claim 3, wherein said two or more mechanical actuators are arranged in an upper part of a backrest of the seat.

5. A seat according to claim 3 or 4, wherein said two or more mechanical actuators are arranged to reproduce a spatial sound that represents at least part of a spatial audio image carried in the audio signal provided as a multi-channel audio signal.

6. An seat according to any of claims 1 to 5, wherein said at least one mechanical actuator comprises at least one moveable magnet mechanically connected to said at least one board.

7. A seat according to any of claims 1 to 6, comprising one or more of the following:

means for adjusting intensity of the sound radiated through said at least one outer surface of the padding,

means for adjusting intensity of the vibration and sound on said at least one outer surface of the padding.

8. A seat according to any of claims 1 to 7, wherein the isolation means comprises first isolation means for mechanically isolating the vibration means from a body of the seat so as to prevent transferring the produced vibration from the vibration means to the adjacent structures via said body.

9. A seat according to any of claims 1 to 8, further comprising a base for mounting the seat, wherein the isolation means comprises second isolation means for mechanically isolating the base from the adjacent structure to which the base is mounted so as to prevent transferring the produced vibration the adjacent structures via the base.

10. A seat according to claim 9, wherein the second isolation means comprises
sensor means for detecting characteristics of vibration transferred from the vibration means to the base, and
damping means for adaptively cancelling the vibration transferred from the vibration means in accordance with detected characteristics of the vibration transferred from the vibration means.

11. A sound reproduction arrangement comprising
a plurality of seats according to any of claims 1 to 10 for reproduction of a respective near-field sound, each of the plurality of seats arranged to receive a first sub-set of audio channels of a multi-channel audio signal; as the input audio signal, and
one or more far-field loudspeakers for reproduction of a far-field sound for said plurality of seats, wherein the far-field sound represents a second sub-set of audio channels of said multi-channel audio signal.

12. An arrangement according claim 11, wherein said multi-channel audio signal comprises one or more front channels, one or more surround channels and a subwoofer channel, and wherein
said first subset of audio channels comprises the subwoofer channel, and
said second subset of audio channels comprises the one or more front channels and the one or more surround channels.

13. An arrangement according claim 11, wherein said multi-channel audio signal comprises one or more front channels, one or more surround channels and a subwoofer channel, and wherein
said first subset of audio channels comprises the subwoofer channel and the one or more surround channels, and
said second subset of audio channels comprises the one or more front channels.

14. An arrangement according to any of claims 11 to 13, further comprising a delay adjustment means for delaying reproduction of the near-field sound in a seat to compensate for the propagation delay in the far-field sound.

15. A method for joint production of vibration and sound in a seat, the method comprising
jointly producing vibration and sound to reproduce an input audio signal by using a vibration means arranged inside a padding of the seat to generate mechanical vibration that is perceivable as a vibration and sound on at least one outer surface of the padding and to radiate a sound through said at least one outer surface of the padding, said vibration means comprising at least one mechanical actuator and at least one board, wherein said at least one mechanical actuator is arranged to vibrate said at least one board in accordance with the input audio signal, and
mechanically isolating the vibration means from adjacent structures.

Drawing