Abstract: A sealed speaker system includes an enclosure and a transducer diaphragm mounted within the enclosure, where an increase in air pressure within the enclosure results in an outward movement of the diaphragm toward an exterior of the enclosure, and a decrease in air pressure within the enclosure results in an inward movement of the diaphragm toward an interior of the enclosure. A pressure vent is provided in the enclosure and allows a gradual transfer of air between the enclosure interior and the enclosure exterior to substantially maintain a pressure equilibrium between the enclosure interior and the enclosure exterior.

Abstract: A miniaturized and portable electronic device with enhanced audio output includes a main body, an internal sound guiding pipe and a surface-mounted but internal loudspeaker. The main body defines a plurality of first sound holes and a plurality of second sound holes at respective ends of the main body. The interconnecting sound guiding pipe receives the portion of the sound waves generated by the loudspeaker which the loudspeaker does not direct to the outside of the main body, and such portion not directly output is collected by the sound guiding pipe to resonate and be transmitted to the second sound holes for outward emission.

Abstract: A portable electronic device including a circuit board, a speaker, an electronic component and an inner casing is provided. The speaker is disposed on the circuit board. The electronic component is disposed on the circuit board and right next to the speaker. The circuit board is disposed in the inner casing including a main cavity, an extended cavity and a channel. The main cavity is connected to the circuit board to define an acoustic chamber for containing the speaker. The main cavity having a first opening. The speaker is connected to the first opening and a part of the speaker is exposed by the first opening. The extended cavity is connected to the main cavity and located above the electronic component. The channel connects the main cavity and the extended cavity, and the extended cavity communicates with the main cavity through the channel.

Abstract: A noise muffler is configured to substantially surround a sound generating object, disposed in or to be disposed in, a structure including a wall or ceiling to be sound limited by, and attenuate sound emitted from the sound generating object, the wall or ceiling including a board having an exposed surface and an opposite surface. The noise muffler has front, rear, left and right sides and a bottom. The sound generating object is positioned in the muffler cavity. The front, rear, left and right sides, and the bottom of the muffler are formed with an outer barrier layer. At least one of the front, rear, left, right sides and bottom of the muffler are formed with a noise absorbing layer positioned adjacent the outer barrier layer to absorb a predetermined amount of sound emitted from the object. At least one of the front, rear, left and right sides includes a first opening into the inner volume of the muffler cavity, the size of which first opening is adjustable.

Abstract: The invention relates to a loudspeaker, which contains bearing structure, a magnetic arrangement (12) fixed to the bearing structure, determining air-gaps (13), and a diaphragm connected to the bearing structure, made of a sheet material. The diaphragm has the shape of a cylindrical jacket consisting of segments (10), the segments (10) are connected to each other along delimiting lines running in the direction of the generating lines, and they have a surface the curvature of which is larger than the curvature that belongs to the overall radius of the cylindrical jacket-like shape, there is a flap (11) at least along two delimiting lines, which flaps (11) extend into an air-gap (13) each radially, and the diaphragm is connected to the bearing structure with flexible supporting units joining the flaps (11) and allowing radial movement of the flaps (11) in the air-gap (13).

Abstract: A battery powered wireless audio speaker comprising a passive radiator is disclosed. The perimeter portion of the passive radiator is sandwiched between the speaker chassis and the retention gasket that resides between an external overlying perforated cover to firmly secure the passive radiator. The construction is capable of being well suited to enhance and improve integrity to the seal between the passive radiator and the speaker chassis in strenuous environment conditions such as when a speaker is submerged in water.

Abstract: A speaker device includes an enclosure provided with a speaker unit and a bass reflex port, wherein the bass reflex port has an outer opening opened to outside of the enclosure and an inner opening opened to inside of the enclosure, and has a tubular body whose hollow cross-sectional area is gradually reduced along an axial direction of the bass reflex port from its ends to its center, and the tubular body is formed so that a length of the hollow cross-section in one direction does not change along the axial direction, and wherein the inner opening of the bass reflex port is located opposite to the speaker unit, with the bass reflex port sandwiched therebetween.

Abstract: A loudspeaker assembly is provided that is suitable for use with a small mobile device, the assembly utilizing a bass-reflex design to increase low frequency efficiency and decrease speaker distortion. The loudspeaker assembly utilizes a single sound port in which the sound pressure emitted by the diaphragm is combined with the sound pressure passing through the bass-reflex channel.

Abstract: A bass reflex port having a tubular shape for air flows, wherein an angle of a first inner radial line with respect to a reference plane including a center axis of the bass reflex port differs from an angle of a second inner radial line with respect to the reference plane, the first line being orthogonal to the center axis and passing a first characteristic point on an inner circumference of the bass reflex port in a first transverse cross section perpendicular to the center axis, the second line being orthogonal to the center axis and passing a second characteristic point corresponding to the first characteristic point and located on the inner circumference in a second transverse cross section perpendicular to the center axis, the first transverse cross section and the second transverse cross section differing form each other in position in a direction of extension of the center axis.

Abstract: A tubular body having an air flow passage, wherein an area of a cross section, in a direction perpendicular to a tube axis, of a space enclosed with an inner wall of the tubular body increases toward an open end thereof, wherein a curvature of the inner wall at an end portion of the tubular body near the open end is repeatedly increased and decreased along a circumferential direction of the inner wall, and wherein, when the inner wall in a cross section of the end portion in the direction perpendicular to the tube axis is viewed from the tube axis, a convex portion at which the inner wall protrudes in a direction away from the tube axis and a concave portion at which the inner wall is recessed in a direction toward the tube axis are repeatedly formed along the circumferential direction.

Abstract: A loudspeaker comprises a reflex port located within the enclosure at a point substantially co-incident with a nodal surface of at least one resonant mode within the enclosure. The amplitude of that resonance at the input to the duct is minimized, hence assisting in filtering out the effect of that resonance without needing absorptive material. Ideally, it is placed at the intersection of two or more nodal surfaces.

Abstract: The inventive subject matter provides a reflex tube for a speaker enclosure and a speaker enclosure that includes a reflex tube, where the reflex tube includes one or more cables and/or connections disposed within it. The connection may be affixed to a connection support, which is in turn affixed within the reflex tube. The connection support may be utilized to reduce air turbulence within the reflex tube.

Abstract: In a low frequency transducer system a multi-compression chamber, an inverse horn structure is employed in combination with a resonance-distortion filter chamber. The filter chamber effectively expands the effective enclosure volume at low frequencies and connected to one of the compression chambers filter parasitic resonances and distortion and allowing the system to more efficiently reproduce low frequencies while being able to use smaller diameter transducers and maintaining good system sensitivity. Compression chambers are organized for constant or continuous compression on a section-by-section basis throughout the inverse horn system.

Abstract: A duct design and methods for designing ducts are described herein. The duct has a profile described by an equation that balances momentum of the fluid flowing through the duct with an adverse pressure gradient. The duct profile is configured to: (i) maintain the fluid's momentum to be greater than the adverse pressure gradient present at any location within the duct, such that no boundary layer separation occurs; and (ii) achieve a fluid exit momentum of approximately zero.

Abstract: A speaker device includes a cabinet from which a duct for adjusting the back pressure protrudes, a speaker unit mounted in the cabinet, and an intermediate hollow member including first and second connection portions. A cabin space in which the cabinet is installed is separated from a non-cabin space by a partition wall. If there is a subframe facing the partition wall, the duct cannot be directly connected to the opening formed in the partition wall. The intermediate hollow member is disposed in a small space between the subframe and the partition wall, the second connection portion is connected to the opening, and the duct is connected to the first connection portion.

Abstract: A low frequency exponential folded horn enclosure employing a bifurcated horn terminal pathway and a single driver with a bifurcated throat channel, with driver access from the top or bottom of the enclosure. The horizontal “butterfly” throat is located at the rear of the enclosure and expands vertically, and the vertically arranged bifurcated horn terminus exhausts in a mostly forward direction on opposite sides of the back chamber which is reflex-ported; said ports arranged to each exhaust into the channel folds at each respective corner of the terminal horn channel.

Abstract: A mounting structure for a speaker with respect to a panel (1) is provided. The mounting structure includes a speaker (20), a pair of projecting latches (10, 11) flanking a predetermined mounting region of the panel (1), and a frame member (30) which is held in fixed engagement with the latches (10, 11) so as to press the speaker (20) onto the mounting region.

Abstract: A speaker device includes a cabinet from which a duct for adjusting the back pressure protrudes, a speaker unit mounted in the cabinet, and an intermediate hollow member including first and second connection portions. A cabin space in which the cabinet is installed is separated from a non-cabin space by a partition wall. If there is a subframe facing the partition wall, the duct cannot be directly connected to the opening formed in the partition wall. The intermediate hollow member is disposed in a small space between the subframe and the partition wall, the second connection portion is connected to the opening, and the duct is connected to the first connection portion.

Abstract: A loudspeaker comprises a reflex port located within the enclosure at a point substantially co-incident with a nodal surface of at least one resonant mode within the enclosure. The amplitude of that resonance at the input to the duct is minimised, hence assisting in filtering out the effect of that resonance without needing absorptive material. Ideally, it is placed at the intersection of two or more nodal surfaces.

Abstract: A printed circuit board for a wireless communications device includes an acoustic path, and acoustically couples microphone circuitry mounted to a surface of the printed circuit board to an exterior of the wireless communications device. A portion of the acoustic path is integrally formed with the printed circuit board and extends generally parallel to the surface of the printed circuit board. One end of the acoustic path is disposed proximate the microphone circuitry and an opposing end opens to receive acoustic sound from the exterior of the wireless communications device. Audible sound propagates through the acoustic path to the microphone circuitry.

Abstract: The present invention relates to speaker enclosures utilizing the golden ratio geometrically throughout the design to reduce reflections, resonance and phase shifting, and to improve the transient response. Enclosures can be box-shaped, trapezoidal, suspended or otherwise configured. The enclosure has a driver wall, a baffle and a rear wall. The driver wall and baffle define a front chamber, and the baffle and rear wall define a rear chamber. The volumetric ratio between the rear chamber and front chamber can be approximately 0.6. The rear chamber also can have braces or dividers that segment the chamber into a central portion and two side portions. The volumetric ratio between the side portions and the central portion can be approximately 0.6. Ports of various configurations are provided. Braces can be used in conjunction with the ports to diffuse the incoming air. The baffle can have a plurality of radiused holes there through.

Abstract: A speaker apparatus according to the present invention includes a phase inversion-type enclosure in which a speaker unit and a bass reflex port are installed, the bass reflex port having a tubular body whose hollow cross-sectional area gradually becomes smaller from one opening side toward an inside of the bass reflex port in an axial direction of the bass reflex port, and a length in one direction of the hollow cross section of the tubular body not changing and constant along the axial direction.

Abstract: A loudspeaker is provided that passively achieves a directional polar response at low frequencies with a high degree of attenuation between the front and the back of the loudspeaker. The loudspeaker 11 has a transducer 13, an enclosure 21 behind the transducer, and port openings 29 in the sidewalls 23 of the enclosure to allow a back-wave produced by the transducer to exit the enclosure and combine with the front wave produced by the transducer. Cancellation behind the loudspeaker at low frequencies is achieved by delaying the back wave with low loss. Low loss delay at low frequencies is achieved by inserting a low-density fibrous fill material 33 in the acoustic chamber 27 formed behind the transducer 13 by the enclosure 21. A fibrous material is selected having a low-pass transfer function and low acoustic loss in its low-frequency pass band.

Abstract: A speaker with acoustic chamber is provided. The speaker includes a main body and an acoustic chamber fixed to the main body. The acoustic chamber can be converted between a collapsed state and an expanded state. The acoustic chamber is drawn to the expanded state to increase the volume of the acoustic chamber and is collapsed to the collapsed state to decrease the volume of the acoustic chamber. When the acoustic chamber is drawn to the expanded state, the quality of the sound output by the speaker is improved.

Abstract: A loudspeaker enclosure accommodates at least one speaker. Sound waves emanating from the rear of the speaker exit through a port in the enclosure. The interior of the enclosure contains at least one partition to lengthen the acoustic path from the rear of the speaker to the port and to cause alternating expansion and contraction of the sound waves emanating from the rear of the speaker. The partitions are arranged in relation to the speaker(s) so as to reduce sound wave reflections that would create non-linearities in the frequency response.

Abstract: Provided herein is a loudspeaker system utilizing one or more ducted slot ports. In various embodiments, a ducted slot port may incorporate an acoustic low pass filter, such as a bend in the airflow path, to control midrange leakage. A ducted slot port may also minimize standing waves within the port duct and control turbulent port noise, such as by varying its cross-sectional area substantially continuously and symmetrically along the port duct's entrance-exit axis.

Abstract: A loudspeaker module includes a hollow main body, two rotatable connecting portions, and two loudspeakers. The hollow main body includes two opposite sidewalls. Each of the opposite sidewall defines a first opening, an inner sidewall of the first opening defines an annular rotating slot. One end of the connecting portion extends an annular flange shaped corresponding to the rotating slot. The two rotatable connecting portions are respectively rotatably connected to the main body via the flange rotating about the rotating slot. Two loudspeakers are disposed in an end of the corresponding rotatable connecting portion away from the main body.

Abstract: A sound enhancer for use with a speaker assembly, comprising a sound manifold forming an enclosure having upper and lower hollow interior portions, the enclosure defining an interior zone within an upper interior portion and having an inlet that faces angularly forwardly, and upwardly, a speaker assembly facing rearwardly through an inlet and into an interior zone to transmit sound rearwardly within the upper interior portion, the enclosure having a back panel to reflect sound transmission downwardly toward and into the enclosure lower interior portion, the lower interior portion having a frontward facing outlet from which sound is transmitted forwardly below the level of the speaker assembly.

Abstract: A headset includes a housing having a first wall with at least one sound hole formed thereon, a loudspeaker unit disposed in the housing and adjacent to the sound hole, a blocking component mounted in the housing and capable of slidably moving towards and backwards the first wall to form an adjunctive chamber therebetween, and an adjustive component rotatably mounted to the housing. The adjustive component is connected with the blocking component in a way of screw link in order to drive the blocking component to move towards and backwards the first wall when the adjustive component is driven to rotate.

Abstract: A loudspeaker enclosure accommodates at least one speaker. Sound waves emanating from the rear of the speaker exit through a port in the enclosure. The interior of the enclosure contains at least one partition to lengthen the acoustic path from the rear of the speaker to the port and to cause alternating expansion and contraction of the sound waves emanating from the rear of the speaker. The partitions are arranged in relation to the speaker(s) so as to reduce sound wave reflections that would create non-linearities in the frequency response.

Abstract: A reconfigurable loudspeaker enclosure. A loudspeaker enclosure, includes a first section that includes a mounting location for an acoustic driver. The mounting location includes a first section mating surface and first section walls, a second section that includes an exit for an acoustic element from which acoustic energy can be radiated. The second section includes a second section mating surface and second section walls. The first section mating surface and the second section are rotatably coupled so that in a first configuration the first section walls and the second section walls are substantially continuous, and so that in a second configuration, the walls of the two sections are substantially non-continuous or perpendicular or both and so that in both the first configuration and the second configuration the two sections are coupled acoustically.

Abstract: An acoustic waveguide with at least two portions coupled by vibration damping structure. The vibration damping structure may be a conformable material such as closed cell foam. The vibration damping structure may further include structure for inhibiting motion in a direction transverse to the interface between the vibration damping structure and a portion of the waveguide.

Abstract: A speaker assembly arrangement for a vehicle is provided that includes a speaker unit including a speaker cabinet defining a first volume and a body part of a vehicle including a hollow member defining a second volume. The speaker cabinet is acoustically coupled to the hollow member by a press-fit coupling having a press-fit direction and mounted on the body part by at least one fastener having a fastening direction substantially perpendicular to the press-fit direction. The body part comprises a first guide arranged and configured to slidably engage with a second guide arranged on the speaker cabinet so that force on the speaker cabinet in the fastening direction is at least in part redirected to the press-fit direction by the slidable engagement of the first guide and the second guide.

Abstract: A waveguide configured to function as a high frequency waveguide for a high frequency sound source mounted to the waveguide, and to function as an acoustical low pass filter for a low frequency sound source mounted behind the waveguide in a multi-way loudspeaker system. The waveguide includes openings that overlay the vibrating surface of the low frequency source. The openings are configured by selection of various geometrical parameters to tailor filtering characteristics as desired.

Abstract: A motorcycle having an open-air cockpit area and a seat configured to receive a rider and position the rider within the open-air cockpit area. A luggage container defines a substantially enclosed cargo volume, and the luggage container is configured to open to provide selective access to the cargo volume. A speaker is configured to output sound in response to signals from a source. A speaker enclosure at least partially encloses the speaker. A bass-reflex passage couples an interior space of the speaker enclosure and the cargo volume of the luggage container.

Abstract: A loudspeaker system includes a loudspeaker enclosure having an inside space, a loudspeaker provided on the loudspeaker enclosure, a first diaphragm which has one of ends fixed to a surface of the loudspeaker enclosure and the other end, a second diaphragm which has one of ends fixed to the surface of the loudspeaker enclosure and the other end, a coupling portion having an elasticity, and coupling the other end of the first diaphragm to the other end of the second diaphragm, an opening structure provided in the surface of the loudspeaker enclosure, and a sealing member provided to a portion among the first and second diaphragms, the coupling portion and an edge part of the opening structure, and closing the inside space to hold an airtightness of the loudspeaker enclosure in a state that the first and second diaphragms can be vibrated.

Abstract: A speaker system includes a cabinet, a front baffle, a speaker unit, a rear baffle, and a fitting member fitted in the rear baffle. The front baffle includes a front duct segment extending backward from the rear thereof. The rear baffle includes an opening portion, a duct connecting portion, and a receiving portion having a semicircular cross section. The receiving portion extends from the opening portion to the duct connecting portion while protruding backward. The opening portion, the receiving portion, and the duct connecting portion have a groove. The receiving portion has an engagement hole. The fitting member having a semicircular cross section is formed by double molding. The frame of the member is made of relatively rigid resin and the rim thereof is made of relatively flexible resin. The frame has an engagement projection. The receiving portion and the fitting member constitute a sealed rear duct segment.

Abstract: A speaker apparatus according to the present invention includes a phase inversion-type enclosure in which a speaker unit and a bass reflex port are installed, the bass reflex port having a tubular body whose hollow cross-sectional area gradually becomes smaller from one opening side toward an inside of the bass reflex port in an axial direction of the bass reflex port, and a length in one direction of the hollow cross section of the tubular body not changing and constant along the axial direction.

Abstract: An acoustic dampening sleeve for electronic equipment and a method of making the same is disclosed. An enclosure for abating noise generated therein includes a housing having a structure defining an internal chamber that has ventilation openings for the ingress and egress of cooling air. The structure cooperates with equipment disposed therein to define intake and exhaust plenums. Air outside the structure passes through the housing ingress opening, into the intake plenum, through the equipment, into the exhaust plenum, and exits the structure through the housing egress opening. The ingress and/or egress openings include baffles. The baffles comprise a resilient material defining openings in fluid communication with the internal chamber and a space outside the housing. The baffles are disposed to prevent or reduce a line of sight between the inside of the structure and the outside of the structure while maintaining open vent channels between the baffles.

Abstract: A reconfigurable loudspeaker enclosure. A loudspeaker enclosure, includes a first section that includes a mounting location for an acoustic driver. The mounting location includes a first section mating surface and first section walls, a second section that includes an exit for an acoustic element from which acoustic energy can be radiated. The second section includes a second section mating surface and second section walls. The first section mating surface and the second section are rotatably coupled so that in a first configuration the first section walls and the second section walls are substantially continuous, and so that in a second configuration, the walls of the two sections are substantially non-continuous or perpendicular or both and so that in both the first configuration and the second configuration the two sections are coupled acoustically.

Abstract: A speaker apparatus according to the present invention includes a phase inversion-type enclosure in which a speaker unit and a bass reflex port are installed, the bass reflex port having a tubular body whose hollow cross-sectional area gradually becomes smaller from one opening side toward an inside of the bass reflex port in an axial direction of the bass reflex port, and a length in one direction of the hollow cross section of the tubular body not changing and constant along the axial direction.

Abstract: A loudspeaker system includes a speaker enclosure that includes a plurality of faces which surround so as to have an internal space tightly closed, a cut-away portion that is cut away along a contour of a virtual plane figure surrounded by a line on one face of the speaker enclosure while a part of the contour as a connection portion is left, a sealing member that covers the cut-away portion so as to tightly seal the internal space of the speaker enclosure, and a loudspeaker that is provided on any face of the speaker enclosure. A portion of the face surrounded by the cut-away portion is a diaphragm capable of vibrating due to bending elasticity while a near portion of the connection portion serves as a point of support. The sealing member is attached to the diaphragm and a peripheral portion which includes a portion of the one face surrounding the diaphragm so as to tightly seal the internal space of the speaker enclosure in a state that the diaphragm can vibrate.

Abstract: A loudspeaker system includes an enclosure having an open end defining a plane, a baffle, a loudspeaker operating in the 4 kHz to 10 kHz range, and a device, preferably a ribbed portion having a plurality of grooves, coupled to the baffle for modifying the spectral profile of the projected sound waves. The baffle includes first and second angled surfaces each oriented at an oblique angle with respect to the plane. The speaker is coupled to the first angled surface and the ribbed portion is coupled to the baffle along the intersection of the first angled surface and the second angled surface. When mounted in a wall or ceiling, the system projects a sound field substantially indistinguishable from that of a loudspeaker located within the listener's listening plane. The baffle can also have acoustic damping material attached thereto, with grooves formed therein, to prevent reflections of 4 kHz to 10 kHz sound.

Abstract: An ultrasonic speaker including: a vibration film having a conductive layer; a pair of fixed electrodes provided oppositely to respective surfaces of the vibration film; and an ultrasonic transducer that causes the vibration film to generate sound waves by applying a DC bias voltage to the conductive layer of the vibration film while applying an alternating signal between the pair of fixed electrodes, and outputs the sound waves generated by the vibration film from two sound wave output surfaces via through-holes provided in each of the pair of fixed electrodes. The two sound wave output surfaces of the ultrasonic transducer are disposed in a direction intersecting with a sound wave emitting direction at right angles.

Abstract: An acoustic waveguide with at least two portions coupled by vibration damping structure. The vibration damping structure may be a conformable material such as closed cell foam. The vibration damping structure may further include structure for inhibiting motion in a direction transverse to the interface between the vibration damping structure and a portion of the waveguide.

Abstract: An apparatus is provided for lowering the fundamental frequency of a cajon drum. A first side wall of the cajon drum is the drumhead. An opening is formed in a second side wall, wherein the opening may be circular, oval, rectangular or other shape. An insert having a cross-section conforming to the shape of the opening is slid into the opening and mounted to the side wall in which the opening is formed. Various techniques for connecting the insert to the side wall of the drum are disclosed. The insert may be fitted into the drum opening during the initial manufacture of the drum.

Abstract: A method and apparatus for providing a loudspeaker assembly is provided. In accordance with at least one embodiment, a method is provided for mounting a loudspeaker driver in a loudspeaker driver aperture defined in a ground plane and installing a grille in relation to the ground plane such that a distance between the grille and the ground plane decreases as the distance from the loudspeaker driver increases. In accordance with at least one embodiment, apparatus is provided comprising a ground plane, a loudspeaker driver mounted in a loudspeaker driver aperture of the ground plane, and a grille positioned relative to the ground plane such that a distance between the grille and the ground plane decreases with increasing distance from the loudspeaker driver.

Abstract: A bass reflex type speaker is disclosed. The bass reflex type speaker includes an enclosure, two speakers, and a bass reflex tube. The enclosure includes a main portion and two protruding portions protruding from the main portion. The main portion defines a sound cavity therein. The protruding portion defines a sound path therein communicating with the sound cavity. The two speakers are connected to the corresponding protruding portion to close the sound path. One end of the bass reflex tube is fixed in the enclosure, and the other end of the bass reflex tube extends out of the enclosure.

Abstract: A sound generator for a vehicle is provided, including a hollow drum having a sound radiation panel structurally and acoustically coupled thereto. The drum has an aperture formed in an outer wall thereof. The drum is adapted to be in fluid communication with an air conduit of the vehicle. The sound radiation panel covers at least a portion of the aperture and is adapted to radiate sound energy to at least one of an engine compartment and an interior of the vehicle. A vehicle system including the sound generator and a method for manufacturing the sound generator are also provided.

Abstract: A speaker module and a mobile device having the speaker module are provided herein. The speaker module includes a speaker unit and a speaker box. The speaker box has a wall defining an aperture receiving the speaker unit therein. The speaker box has a first speaker chamber, a second speaker chamber and a connecting section connecting the first speaker chamber and the second speaker chamber. The cross-sectional height of the space of the connecting section is lower than that of the first speaker chamber or the second speaker chamber. In other option, the space of the connecting section is smaller than that of the first speaker chamber or the second speaker chamber.