SE1630240A2 - Sound valve - Google Patents

Abstract

A method and apparatus that delivers controlled air, sound and silence efficiently and invisibly to the user is revealed. A method of controlling air exchange rates in locale, cancelling fan and ventilation noise, and generating sound or silence from DC to 20 kHz using the apparatus and the microphone (s) of a mobile device is also revealed.The apparatus comprises existing or integrated ducts and fans, motirized air valves using acoustic membranes, hydraulic interconnects, air and spring suspensions, pressure sensors, wireless systems, and control logic.Intuitive presence, motion and gesture control of the ventilation, silencing, audio volume, audio center direction and channel separation is described.

Description

SOUND VALVE FIELD OF THE INVENTION

[0001] The present invention relates to user’s need of sound, silcence and air in locale with controlled ventilation or forced air circulation. It improves both the energy efficiency, frequency range, audio fidelity and usability compared to traditional loudspeaker, active noice cancellation and ventilation control systems.

BACKGROUND OF THE INVENTION

[0002] Pesent art ventilation control systems, particularly in modem energy-efficient buildings, are designed to be highly efficient air movers but are inherently noisy and difficult to tune to user’s actual need of air. This leads to installments with either large dimension both in pipings, fans, sound blockers, sound absorbents and air diffusors, or a persistent noise that is often peaking in the 10-100 Hz range. Active noice cancellation using low-cost speakers does not cover this range. Also, the air circulation does not follow the user’s need but is to a large extent wasted in empty areas. Together, this lead to unhealth and large environmental impact per person, particularly in large locale.

[0003] Present art loudspeakers are designed to be highly linear air vibrators, but have several inherent limitations: 1. Limited frequency range per vibrating membrane, leading to complex speaker constructions and arrangements that intrude on the living area. 2. Membrane breakup into multiple resonances at higher frequencies, leading to a disharmonic reproduction of sound. 3. Multiple membranes introduce phase shift, leading to unstable reproduction of sound source locale. 4. Inefficient at frequencies below ~200 Hz, leading to limited sound pressure.

. Large, heavy, extremely inefficient and bandwidth-limited at frequences around ~20 Hz. Such sound is usually only reproduced to ears in headset speakers or to the body in special chairs.

[0004] This means the user need of sound and silence is always compromised, particularly in large locale. Frequences below -100 Hz for example, can be dropped completely which adds a sensation of “boxiness”. That frequency content can also be bundled together into a single speaker cabinet resonance adding “rumble”. It can also artificially be shifted into higher harmonics adding “tension” to the sound.

[0005] Another example is that sound reproduction in the middle to high hearing frequencies changes dramatically depending on position due to phase shift between membranes as well as room resonances.

[0006] What is needed is a better means of delivering air, sound and silence to the user, and to achieve this without cluttering the locale with bulky installments.

OBJECTS OF THE INVENTION

[0007] The object of this invention is to deliver controlled air, improved sound and complete silence efficiently and invisibly to the user.

SUMMARY OF THE INVENTION

[0008] In order to overcome the problems with bulky and noisy ventilation systems that wastes air on empty spaces, we do the following: 1. Employ noise and presence detection by measuring sound both from inside the ventilation and from the user's mobile device. 2. Feeding a combined air and noise cancellation signal to a membrane valve that we make linear from 0 to ~200 Hz frequency. 3. Cancel frequences above ~200 Hz using the same cancellation signal, by an air vibration action from the same membrane.

[0009] This membrane valve replaces the normal vent(s) of the locale, making it easy to install, invisible to the occupants, and can be made self-powered by using an impeller hidden in the valve. Both the noise and unwanted air is hereby cancelled out - the former at the user’s location and the latter at empty areas. Fresh air and complete silcence follows the user and the ventilation system can be made smaller.

[0010] In order to improve on the problems with frequency-limited, complex, disharmonic, unstable, inefficient and intruding loudspeaker systems, we use the silent vent above [0008]. We do the following: 1. Add a wanted sound signal to the noice cancelling - turning the vent valve it into a calibrated, deep-frequency and noise-free speaker. 2. Membrane breakup is pushed to higher frequency through a stabilizing air pressure, leading to a raised upper frequency limit and less disharmonies.. 3. The phase shift between speakers is eliminated, leading to a stable and more correct perception of sound source locale. 4. frequencies below ~200 Hz axe generated at high sound pressure from the vented air - without consuming any extra energy.

. The installation is simple [0009] and non-intruding. 6. Functionality for follow-me air, follow-me silence, follow-me sound and channel separation is constrolled by the user just moving around naturally.

[0011] The valve membrane will vibrate air in front of it like a normal loudspeaker at typical loudspeaker frequencies, and simulataneously modulate the air How for generation of sound at lower frequences. That low-frequency sound pressure is only limited by the capacity of the ventilation system, which for most locale is > 120 dB. Typical installations can have a flat ~80 dB frequency response in the full sound frequency range 10 Hz to 20 kHz (including both body motion sensing and hearing) using only two motors coaxially mounted in the valve: One outer motor that drives a valve membrane from DC to ~ 2 kHz and one motor that drives a front tweeter membrane between ~2 kHz and 20 kHz. A method for driving both these membranes using a singe motor is also described but has not yet been tested.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] For a more complete understanding of the invention, reference is made to the following description and accompanying drawings, in which:

[0013] PIG. 1 Details of a speaker valve;

[0014] FIG. 2 Main parts in an entry vent speaker;

[0015] FIG. 3 Main parts in an exit vent speaker;

[0016] FIG. 4 A pressurized duct or cavity vith entry and exit valve speakers;

[0017] FIG. 5 Entry vent speaker using rear-facing passive bass reflex membrane;

[0018] FIG. 6 Exit vent speaker using forward-facing passive bass reflex membrane;

[0019] FIG. 7 Entry vent speaker using speaker surround;

[0020] FIG. 8 Entry vent speaker using diffusor-shaped passive bass reflex membrane;

[0021] FIG. 9 Vent control system;

[0022] FIG. 10 Vent feedback method;

[0023] FIG. 11 On-off control of entry and exit valves at 20 Hz for an 12/hr air exchange rate;

[0024] FIG. 12 Cosinusoidal control of entry and exit valves at 20 Hz for an 12/hr air exchange rate;

[0025] FIG. 13 Typical total-energy-optimized cross-over filters and resulting membrane motion (excursion) for standard n and dB requirements for a living room (5/hr, 80 dB), restaurant (12/hr, 70 dB) and library (4/hr, 50 dB).;

[0026] FIG. 14 Geometry, coordinates and streamlines for a cross section of the How between membrane and wall;

[0027] FIG. 15 Optimized wall shape and resulting valve action; and

[0028] FIG. 16 Result of feedback control algorithm zp() on noice cancellation and sound generation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The arrangement in FIG. 1 shows the inner workings of an air valve capable of cancelling or generating audible as well as infra-sound at high efficiency. It shows a duct wall [1] with inlet [2] and outlet [3] ends, and a leight- weight membrane [4] for controlling the flow of a fluid [5] such as air. When the membrane is moved closer, further from or vibrating towards the wall, there is a closing action [6], opening action [7] or vibrating action [8], respectively, of the fluid flow. This flow action is made laminar and linear to the membrane position, as described later. A membrane actuator [9] such as a voice-coil, magnet and spider suspension arrangement is required. It must be capable of rapid and precise positioning of the leightweight membrane from DC to audible frequencies. Somewhere connected to either end of the duct, a compressor means [10 ] is also required for generating a generally constant absolute pressure on that end of the duct. The pressure acting on membrane [11] adds tension that pushes breakup modes to higher frequency and lower amplitude, which therefore makes the membrane a better acoustic element. The air flow around the membrane edge creates an air pillow [12] that counteracts side-movements and therefore make the motion more precise. When that motion is vertical, the precision is further increased due to lack of gravitational pull sideways. When the membrane surface is mostly perpendicular to the transferred flow [13], air swirls [14] with nearly the same rotational air speed as the transferred air will exist on each side of the membrane, and these act as local reservoirs for flow rate changes. These flow reservoirs are important to faciliate in the design since they make the operation quiter and faster: With reservoirs rapid flow rate changes happens through small and laminar air direction changes (quitely) for good sound valve operation at high frequency. Without them the rapid flow rate changes happens by abrupt and therefore turbulating air speed changes (noisy) so that good sound valve operation is limited to lower frequencies. These generic design requirements are summarized in claim 1.

[0030] The arrangements in FIG. 2 and FIG. 3 shows exemplary arrangements of a preferred embodiment for noise-free inlet air to a room and outlet air from a room, respectively. In FlG. 2, one sees a vent tube [17 ] with a preferable expansion of the inner wall in the air flow direction. A speaker [16] assembly with its membrane in a preferable orientation against the air flow is held by a frame [15] so that the speaker membrane edge is centered in the tube [17] expansion. Air flow is designed to be linear with the membrane position as described later. The membrane motion can cancel incoming pressure variations very efficiently and also quickly control the static pressure and air exchange rate in the room. An optional fan [18] assembly is used for energy harvesting and pressure boosting. In FIG. 3 the frame [15] functions as decoration and dust filter for the speaker [16] assembly which in this case is held by a hidden grip inside the tube [17].

[0031] The arrangement in FIG. 4 shows similarly exemplary arrangements of preferred embodiments for stand-alone noice cancellation (claim 2) and sound generation (claim 3) using one or more pressurized duct or cavity. The stand-alone unit can be for example an air conditioner, a vacuum cleaner, an air purifier/dryer/humidifier, a wall or speaker cabinet, or a duct between two far ends of an arena. It can use any volume large enough to accomodate a substantial amount of pressurized air, or any duct with ends farther apart than the longest wavelength of sound to be controlled, as described later. The suction speaker [19] controls air passing through a preferaby centrifugal and/or forward-bent fan [18] (claim 4) which pressurizes a duct or cavity [20]. A pressure speaker [21] controls air release from the duct or cavity [20].

[0032] The arrangements in FIG. 5 and FIG. 6 shows similarly exemplary arrangements of preferred embodiments for full-spectrum sound generation in a room - the former for inlet air and the latter for outlet air. The frame [15] holds a speaker [16] assembly containing a front-firing speaker and a rear passive bass reflex membrane that protrudes into the tube [17] expansion. Back pressure variations in the speaker [16 ] box result in hydraulic motion of the protruding membrane. This low-frequency motion changes the air flow aperture and the resulting room pressure, resulting in low-frequency sound at high amplitude as described later. The design requirements are summarized in claim 7.

[0033] The arrangements in FIG. 7 and FIG. 8 shows similarly alternative arrangements for sound generation from incoming air into a room - the former for lower frequency ventilation and noise control, and the latter for full-spectrum sound. In FIG. 7, the frame [15] holds a rear- facing flexible surround of a speaker [16] assembly that is mounted in an inlet tube [17]. The air valve action is here between the rear of the speaker surround and a fixed plate. In FIG. 8, the frame [15] holds a speaker [16] assembly with passive bass element that act as diffusor for incoming air. The air valve action is here between the diffusor membrane and a fixed tube [17].

[0034] The system in FIG. 9 and method in FIG. 10 illustrates auxiliary devices, electronics, signal processing and applications needed for precise control of air flow, noise cancellation, and full-spectrum sound in a room according to the present invention. In FIG. 9 which is used in claim 9, the system [ 22 J contains one or more speaker [16] that is wirelessly connected to one or more mobile device [23]. The latter is used to control the ventilation, noice cancellation and sound generation by its presence (claim 10), position and gestures (claim 11). In FIG. 10 which is used in claim 12, the air control method [24] uses one or more ventilation and sound generation method [ 25 J such as the one described above in concert with a ventilation and sound signal transmission method [ 26 ] that maintains a calibration for both an air flow model as described later, a noise model (claim 14) and a sound generator model (claim 13) in the mobile device. The result is finer-timed control of both the ventilation, noice cancellation and sound generation, as described later.

Other considerations [0035] A specific percussion sound with extra fast attack and deep bass, suitable for large arena use, can be generated very efficiently through claim 5. Here the membrane intentionally accelerates by increasing fan pressure and suction until it lands with an explosive sound or bounces with a smashing sound.

[0036] For narrow inlet vent designs such as those in high-pressure diffusors with long throw, claim 6 describes an alternative. In FIG. 1, the two air swirls [14] needed for noise-free high-frequency operation are typically rather small and unstable, and can therefore be limited in capacity, but here that is not a limitation since boths sides of the membrane take part in a large 8-shaped swirl that is (in a state-of-theart long-throw diffusor) laminar and stable by design.

[0037] Installation of sound- and air-managing vents into an existing ventilation system offers excellent scalability since the performance depends on known air exchange rates rather than varying room sizes, as detailed in claim 8. However, if the rich bass sound generation capability is used in one such vent, that bass sound spreads to all other vents in the same channel. Therefore silence needs to be taken care of first: A bass-generating vent may require all other vents connected to the same channel to use noice cancelling (claim 2).

Analysis of air flow, air volume and resulting pressure variations [0038] The most extreme sound pressure in a ventilated room is achieved by two vent speaker valves that alternates between fully open and fully closed position FIG. 11. The sound pressure gradient is then -{n*’bar}/’hr. A sinusoidal control FIG. 12 result in a sound pressure 20*log10(n/{sqrt(2)*2*t*f}*'bar/{’p.0*’hr}) dB. At n = 12/hr as required for a restaurant, a 20 Hz tone can reach almost 100 dB sound pressure, but falls off as 1/f at higher frequency.

[0039] In order to keep the frequency response flat, the membrane position needs to follow a low-pass filtered derivative of the signal multiplied by f/n, combined with a high-pass filtered raw signal (the desired sound). The upper frequency f_upper = n/{sqrt(2)*2*? *’p.0}*’bar/’hr*10^{-dB/20} for valve-generated sound is in the range 80-2000 Hz depending on sound pressure requirements and available air flow. Typical total-energy-optimized cross-over filters and resulting membrane motion (excursion) is shown in FIG. 13 for standard n and sound pressure requirements for a living room (5/hr, 80 dB), restaurant (12/hr, 70 dB) and library (4/hr, 50 dB). Note in FIG. 13 the very small and power-efficient excursions at lower frequences, when the sound pressure is generated by modulating large iiows from efficient fans rather than by pushing just the small volumes of air in front of the membranes.

Valve design [0040] A loudspeaker valve has an expansion in the wall where sound is generated by varying the air flow - larger flow as the speaker membrane moves downstream and smaller flow as it moves upstream. The following calculation is for designing the wall radius R(z) of the expansion so that the resulting sound has a minimum of harmonics.

Pipe diameter D.p:125*’mm Speaker membrane diameter D.m:100*’mm Maximum linear membrane offset x.max:10*’mm Maximum nonlinear membrane offset x.mech:15*’mm

[0041] Assumptions: 1. The driving pressure is constant. 2. Transferred streamlines are parallel with wall closest to membrane edge. 3. The flow is proportional to a valve constriction area A that is orthogonal to the transferred streamlines. 4. The membrane accomodates a large swirl of non-transferred streamlines on each side, where flow-changes for sound generation can be grabbed and returned easily, i. e. by ony a (small) change in direction for the affected streamlines near the edge of the membrane.

[0042] The wall shape R(z) should have the following properties: (1) R(-x.mech)?D.m/2+tol - Valve is as closed as possible without (tol) risk of friction when membrane is in its most upstream position. (2) R(+x.mech)=D.p/2 - Valve is as open as possible when membrane is in its most downstream position. (3) diff(R(-x.mech),z)?0 - Entry wall connects to an axial flow. (4) diff(R(x.mech),z)?0 - Exit wall connects to an axial flow. (5) for(z,range(-x.mech,x.mech),diff(A(z),z) ?0) - Valve opens in the downstream direction. (6) for(z,range(-x.max,x.max),diff(A(z),z,2)?0) - Minimum flow cross section A is linear with membrane position.

[0043] The cross section A(z) in (6) has the shape of a cut cone from an upstream position zw < z where the valve wall is perpendicular to a membrane edge at z. The geometry, coordinates and streamlines are sketched in FIG. 14. From the coordinates in the marked triangle [ 37 ] we get: (7) {z-zw}/{R(zw)-D.m/2}? Image available on "Original document" ?diff(R(zw),z) (8) S^2?(z-zw)^2+ (R(zw)-D.m/2)^2 From (7, 8) we obtain mappings from zw to z and A: (9) zw2z(zw):zw+(R(zw)-D.m/2)*diff(R(zw),z) (10) zw2A(zw):?*(R(zw)+D.m/2)*sqrt(((R(zw)-D.m/2)*diff(R(zw),z))^2+(R(zw)-D.m/2)^2)

[0044] There is no exact mapping from z to A. We used a finite difference grid for zw where the properties can be calculated. An optimized wall shape and resulting valve action is shown in FIG. 15.

Result: A0:25*’cm^2 A1:2*{’cm^2}/’mm C.d:0.9 Noice cancellation and sound generation through feedback [0045] Room and ventilation example: V.0:2.4*’m*3.2*’m*5*<,>m 'T.0:293.15*’K ?p:50*’Pa ’kT:eval(’k.B*'T.0) N.0:eval({’?.0*V.0}/{M/’N.A}) p.max_push:(m.i+m.o)*eval({?/4*(D.m^2-D.mi^2)*x.max}/V.0*’bar) dB.max_push:20*log10(p.max_push/{sqrt(2)*’p.0})

[0046] Model: (11) ?V(z.i,z.o):?/4*(D.m^2-D.mi^2)*(m.i*z.i+m.o*z.o) - Room volume change per membrane (12) ?1(p.i,p.?,p,z.i,z.?):((?0-?1*z.i)*sqrt({2*(??+p.i-p)}/’?.0)-(?0+?1*z.?)*sqrt({2*(?pp.o+p)}/<,>?.0))*C.d*’bar/’kT - Room molecule count change rate

[0047] Excursion needed for cancelling noise in input and output pipes and generating sound: zp(n,dB.i,dB.o,dB,m.i,m.o,f): - audio(t):sin(2*?*f*t) - audiol(t):diff((audio(t)),t) - f.c:eval(fboom(n,dB.max_push)) - dt:0.04/f - t:range(0,(I-1)*dt,dt) - for(i,range(1,I) - - el(p.i,i):eval(’p.0*10^{dB.i/20}*audio(el(t,i))) - - el(p.o,i):eval(’p.0*10^{dB.o/20}*audio(el(t,i))) - - el(p,i):eval(<,>p.0*10^{dB/20}*audio(el(t,i))) - el(N,1):N.0 - el(z.i,1):0*’mm - el(z.o,1):0*’mm,d:1*’?m - for(i,range(1,I-1) - - e(d.i,d.o):eval(’kT*({el(N,i)+N1( - - - {el(p.i,i)+el(p.i,i+1)}/2, - {el(p.o,i)+el(p.o,i+1)}/2, - {el(p,i)+el(p,i+1)}/2, - el(z.i,i)+d.i/2, - el(z.o,i)+d.o/2 - - - )*dt}/{V.0+?V(el(z.i,i)+d.i,el(z.o,i)+d.o)}-N.0/V.0)-el(p;i+1) - - de_di:{e(d,0)-e(-d,0)}/{2*d} - - de_do:{e(0,d)-e(0,-d)}/{2*d} - - el(z.i,i+1):el(z.i,i)-( - - - if de_di?0 - - - e(0,0)*de_di/{de_di^2+de_do^2 - - - else - - - - 0) - - el(z.o,i+1):el(z.o,i)-( - - - if de_do?0 - - - e ( 0 , 0 ) *de_do / { de_di^2+de_do^2 } - - - else - - - - 0) - - el(N,i+1):eval(el(N,i)+N1({el(p.i,i)+el(p.i,i+1)}/2,{el(p.o,i)+el(p.o,i+1)}/2,{el(p,i)+el(p,i+1)}/2 - - el(p,i+1):eval('kT*(el(N,i+1)/{V.0+?V(el(z.i,i+1),el(z.o,i+1))}-N.0/V.0)) - augment (t/’ms,z.i/x.max),augment(t/'ms,z.o/x.max),augment(t/’ms,p/p.max_push)

[0048] The result of feedback control of noice cancellation and sound generation using the algorithm above for some typical and extreme noise and sound signals are plotted in FIG. 16.

[0049] It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, because certain changes may be made in carrying out the above method and in the construction(s) set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

[0050] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Claims (14)

What is claimed:

1. A valve speaker (FIG. 1), comprising; a duct wall [1] having an inlet [2] and an outlet [3], and a membrane [4] for controlling the flow of a fluid [5] in conjunction, wherein said membrane having a closing action [6], wherein said membrane [4] abutting said duct wall [1]; such that the fluid [5] between said duct wall [1] and said membrane [4] is decreased; an opening action [7] , wherein said duct wall [1 ] having an aperture between said membrane [4] and said duct wall [1]; such that the fluid flow between said duct wall and said membrane [4] is increased, and, a vibrating action [8] between said closing action and said opening action, wherein said membrane [4] is configured for a laminar flow that is linear to the position of said membrane for generation of sound; and, an actuator [9] for moving said membrane with respect to said duct wall; and a compressor means [10], preferably for generating a constant pressure in said inlet or said outlet; wherein said membrane is enclosed by said duct wall or said duct wall is enclosed by said membrane; preferably said membrane is light-weight; preferably said air flow stabilizes the shape of said membrane; preferably said air flow creating an air pillow [12] that counteracts side-movements of said membrane; preferably said motion of said membrane is vertical; preferably the edge of said membrane is in general perpendicular to the transferred flow [13], with substantial and laminar air swirls [14] on each side of the membrane.

2. Valve speaker according to claim claim 1, wherein said membrane is configured to move out of phase with an existing variation in said fluid flow.

3. Valve speaker according to claim claim 8, wherein said membrane is configured to move in phase with a desired variation in said fluid flow.

4. Valve speaker according to claim claim 1, wherein said membrane having said opening action towards said outlet; preferably wherein said compressor comprises rotor blades having an increasing angle with respect to said fluid flow.

5. Valve speaker according to claim claim 1, wherein said compressor comprises rotor blades having a decreasing angle with respect to said fluid flow; and said membrane having said closing action towards said outlet; preferably said closing action is primarily flat; preferably said valve speaker is a percussion instrument, or said actuator is hand- or drumstick-operated, or said actuator is foot-pedal operated.

6. Valve speaker according to claim 1, wherein said fluid flow enters an edge of said membrane; preferably said actuator is piezoelectric; preferably said membrane constitutes a slot opening in said duct wall.

7. Valve speaker according to claim 1, wherein said membrane comprises a preferably flexible connection to said actuator; and said membrane has a certain weight; preferably said connection is a compressible fluid; preferably said actuator is the main speaker element of a closed loudspeaker box and said membrane also constitutes its passive bass reflex element.

8. Valve speaker according to claim 1, where said compressor is a ventilation or air conditioning means, preferably said fluid flow changes the air in the room 5-20 times per hour during occupancy; preferably said fluid flow variation during said vibration reaches at most 50-80% on average of said fluid flow; preferably said valve is part of a flow-regulated ventilation system.

9. Valve speaker system FIG. 9, comprising; one or more [16] according to claim 1 to claim 8; a [23] provided by a user; wherein movement of said [23] by said user controlling a mode of one or all of said one or more [16]

10. Valve speaker according to claim claim 9, wherein said mode is activating or deactivating said [16]; preferably said movement changes the distance of said user to said [16].

11. Valve speaker according to claim claim 10, wherein said movement of said mobile device by said user comprises: a. a lift motion, wherein said mode is enabling a sound settings adjustment; or b. a lowering motion, wherein said mode is disabling a sound settings adjustment, or c. a motion towards one of said one or more valve speaker, wherein said mode is increasing the audio volume or reducing the audio volume or increasing the audio channel separation of said one of said one or more valve speaker; or d. a motion from one of said one or more valve speaker, wherein said mode is decreasing the audio volume or increasing the audio volume or decreasing the audio channel separation of said one of said one or more valve speaker; or e. a vertical circle or vertical ellipse motion towards one of said one or more valve speaker, wherein said mode is increasing or decreasing the audio volume of said one of said one or more valve speaker; or f. a horizontal ellipse motion towards one of said one or more valve speaker, wherein said mode is increasing or decreasing the audio channel separation of said valve speaker; or g. a horizontal circle motion, wherein said mode is raising or lowering the audio volume of all of said one or more valve speaker. h. a lift-and-lowering motion, wherein said mode is switching on the audio volume of all of said one or more valve speaker. i. a lowering-and-lift motion, wherein said mode is switching off the audio volume of all of said one or more valve speaker.

12. A method FIG. 10 for transmission of sound, comprising; [ ] transmitting a sound from a valve speaker according to claims claim 1 to claim 8 to a mobile device having microphone means; [ ] transmitting a desired sound signal over at least one communication channel from said mobile device to said actuator; preferably wherein said at least one communication channel are chosen from the group Bluetooth, WiFi or UWB; preferably amplitude and/or delay in said sound in said microphone from said valve speaker, and/or signal amplitude and/or signal delay in said at least one communication channel, is used to track movement and/or magnitude of movement and/or position of at least one said user.

13. Method according to claim claim 12, comprising; compensating said sound from said valve speaker by the spectral and/or temporal and/or air-flow dependency of said sound from said valve speaker in said microphone; preferably the frequency response of said microphone is flat to < 0.1 dB in the range 10 Hz 20 kHz.

14. Method according to claim claim 13, comprising; counter-acting remaining unwanted sound in said microphone by generating out-of-phase said unwanted sound from said valve speaker at said microphone; wherein said counter-acting round-trip is faster than the variations in said unwanted sound or faster than the variations in a model of said unwanted sound; preferably said round-trip is 2-50 ms.