Abstract: A membrane 103 for an acoustic device 100 is provided, the membrane 103, wherein the membrane 103 comprises a central portion 212, an annular portion 105, and a corrugation 107, wherein the annular portion 105 is arranged around the central portion 212, wherein the annular portion 105 is adapted to be fixed to a coil 106, and wherein the corrugation 107 is arranged between the central portion 212 and the annular portion 105. Thus, the corrugation 107 may form an inner corrugation compared to an outer corrugation 104 which would be arranged farther away from the central portion 212 than the annular portion 105.

Abstract: A system providing a resonator for a transducer of an electronic device is provided. The system comprises a housing defining: a first enclosure having a first opening to house a back end of the transducer and a second opening; a port connected to the first enclosure through the second opening of the first enclosure, the port having a first end, a second end, an interior channel and a second opening in the second end; a second enclosure to cover a front portion of the speaker; and at least one aperture defined in the second enclosure to allow air outside of the electronic device to be in communication with the front of the transducer. When the transducer is mounted into the first enclosure, a first volume between the transducer and the first enclosure is formed which is in communication with air surrounding the second end of the port.

Abstract: Multiple Helmholtz resonators are combined serially and dynamically to mitigate and/or overcome acoustic noise filtering problems. One Helmholtz resonator is attached to a duct having an acoustic flow path channel containing undesired acoustic signals (noise) and is considered to be an immovable Helmholtz resonator with respect to that flow channel, while at least one movable Helmholtz resonator is movably and acoustically coupled to the immovable Helmholtz resonator. The immovable and movable Helmholtz resonators are acoustically coupled together to adjustably filter two resonant frequencies in the flow path channel with a feedback control system that adjusts the position of the movable Helmholtz resonator in response to the differences in pre-filtered noise versus filtered noise.

Abstract: [Problem to be Solved] To provide a high-sensitive compact vibration pickup microphone, suitably used as a talking microphone in high ambient noise environments or as a speech recognition input microphone, with high microphone sensitivity, resistance to sliding noise, and insensitivity to external noise and vibration.

Abstract: An exemplary earphone module includes a faceplate, a bottom cover connected to the top cover, and a microphone received between the faceplate and the bottom cover. The faceplate defines a sound hole therein. The microphone defines a Helmholtz resonance chamber therein. A washer is placed between the faceplate and the microphone. The washer has a sound chamber communicating the sound hole with the Helmholtz resonance chamber. The Helmholtz resonance chamber has a volume V, the sound hole has a diameter d and a length l, and the sound chamber has a diameter D. The diameter D of the sound chamber meets the equation D=d or the formula D ? 4 ? V ? ? ( l + 0.8 ? d ) .

Abstract: The present invention is an extremely low frequency (ELF) microphone and acoustic measurement system capable of infrasound detection in a portable and easily deployable form factor. In one embodiment of the invention, an extremely low frequency electret microphone comprises a membrane, a backplate, and a backchamber. The backchamber is sealed to allow substantially no air exchange between the backchamber and outside the microphone. Compliance of the membrane may be less than ambient air compliance. The backplate may define a plurality of holes and a slot may be defined between an outer diameter of the backplate and an inner wall of the microphone. The locations and sizes of the holes, the size of the slot, and the volume of the backchamber may be selected such that membrane motion is substantially critically damped.

Abstract: There is provided a sound field adjusting method that can provide an acoustic improvement effect tailored to the characteristics of various acoustic rooms, with small differences in reflection properties between sound receiving points. The diameters of a plurality of columnar reflectors are calculated so as to diffuse sound waves of respective different frequency ranges. An arrangement condition is calculated so that the columnar reflectors having the calculated diameters form a plurality of reflecting surfaces that reflect the sound waves of different frequency ranges in random reflection directions, with random reflection time delays, or in random phases. The plurality of columnar reflectors having respective different diameters are then arranged under the arrangement condition.

Abstract: A speaker used as a household appliance is provided. The speaker has an ultra-slim structure suitable for an ultra-slim TV and is applied to a woofer speaker representing a superior low-pitched sound characteristic. The speaker has the ultra-slim structure and improves the low-pitched sound characteristic and sound pressure by increasing the amplitude. Outer appearances of a damper and a frame are changed to enlarge a diameter of a voice coil in comparison with an outer diameter of the speaker, the damper has a two-step structure such that a longitudinal amplitude of an upper side of the damper is increased to improve the low-pitched sound characteristic in a state in which a lower side of the damper is put on the frame, and a size of a vibration plate is enlarged to improve the low-pitched sound characteristic and sound pressure. A flat plate is used as the vibration plate.

Abstract: An improved structure for the compositely formed sound box consists of a plastic-made box with one-way opening and intensified rib and inlet components provided inside the box. The main feature is the bubbled one-piece soundproof layer inside the sound box to expand the overall structure of the sound box, reduce the thickness of the sound box, minimize the thickness of the shell, and upgrade the soundproof performance at the same time.

Abstract: A speaker with vibration absorbing function is disclosed in the present invention. The speaker is disposed on a boss of a casing. The speaker includes a sound box, and a supporting arm disposed on a lateral surface of the sound box. The supporting arm includes a bending portion. An end of the bending portion is connected to the sound box. The supporting arm further includes a hooking portion disposed on the other end of the bending portion for hooking the boss of the casing. Vibration generated from the sound box can decay by the bending portion, and is not transmitted to the boss via the hooking portion.

Abstract: The present invention relates to a loudspeaker in the acoustic field and the information communication field. The invention provides a loudspeaker that can realize a thinner size. To achieve this, the loudspeaker of the present invention is structured so that a part of a diaphragm is inserted to a dent or an opening formed at the center poles of a lower plate of a magnetic circuit. This structure allows the diaphragm to be stored within the height of the magnetic circuit, thus allowing the loudspeaker to have a thinner size.

Abstract: The present disclosure relates to a sound box structure for an electronic apparatus. The sound box structure is disposed in an electronic apparatus and comprises a resonating cavity, a loudspeaker, and at least an electronic device. The loudspeaker and the electronic device are disposed in the resonating cavity. The present disclosure mainly combines the sound box structure disposed originally in the electronic apparatus with the accommodating space of other electronic devices for expanding the resonating space of the sound box structure for the electronic apparatus. Consequently, the output audio quality of the sound box structure for the electron apparatus can be improved, and hence enhancing the multimedia effects of the electronic apparatus.

Abstract: An apparatus and method of providing an apparatus, the apparatus including: a loudspeaker configured to convert an electrical input signal into an acoustic output signal; and carbon nanohorn material wherein the carbon nanohorn material is positioned so as to be exposed to the acoustic output signal.

Abstract: A resonator for a transducer of an electronic device is provided. The resonator comprises: a first enclosure having a first opening to receive a back end of the transducer and a second opening; and a port connected to the first enclosure through the second opening of the enclosure, the port having a first end, a second end, an interior channel spanning from the first end to the second end. When the transducer is mounted into the first enclosure, a first volume between the transducer and the enclosure is formed which is in communication with air surrounding the second end of the port through the interior channel of the port. A second enclosure to cover a front portion of the transducer may be provided.

Abstract: A microphone arrangement includes a housing having a sound hole, a first input audio transducer with a first sensitivity and a second input audio transducer with a second sensitivity. In this microphone arrangement, the first and the second input audio transducers are arranged in the housing, such that the first input audio transducer is directly acoustically coupled with the sound hole and the second input audio transducer is indirectly acoustically coupled with a sound hole via the first input audio transducer.

Abstract: An apparatus comprises: a transducer configured to generate sound; and a housing defining a first cavity and a second cavity, the first cavity and the second cavity being connected to the transducer; wherein the first cavity comprises a first sound outlet at a first surface of the housing; and the second cavity comprises a second sound outlet at the first surface of the housing and a third sound outlet at a second surface of the housing wherein the first and second cavities and the first and second sound outlets are configured to limit a sound pressure level of the generated sound at the first and second outlets at one or more frequencies.

Abstract: A method and apparatus for a multi-chamber ported stereo speaker is disclosed. The stereo speaker is a single unit with multi-chambers in an enclosure box. The multi chamber ported speaker comprises an enclosure housing a shared acoustic chamber having an external port for allowing air external of the enclosure box to flow into the shared acoustic chamber, and at least two additional chambers comprising a corresponding internal port in each additional chamber for forming an air pass from each additional chamber with the shared chamber, each additional chamber comprising a corresponding driver mounted through a wall of the chamber and enclosure box for forming the ported speaker.

Abstract: A loudspeaker assembly is disclosed for use in a loudspeaker system having infinite baffle topology. The assembly comprises a driver including a cone and a basket and at least one Helmholtz resonator including a chamber and a vent duct communicating with the chamber and adapted to pass through the infinite baffle. The chamber is dimensioned to provide a tuned frequency well above an operating band associated with the driver. The cross sectional area and length of the vent duct may be set to provide control over duct air noise and low frequency extension. A method of tuning a loudspeaker assembly for use in a loudspeaker system having infinite baffle topology is also disclosed.

Abstract: A system for forming hearing protectors, an ear cup of such a system and a hearing protector formed from such a system. The system includes a number of first ear cups and a number of second ear cups, the first and second ear cups having noise-reducing spaces of different size, and at least one electronic unit with at least one speaker. This system allows the same type of electronic unit to be used for ear cups with different degrees of noise attenuation.

Abstract: A sound transducer for the transmission of audio frequency signals with a pressure-voltage transducer is provided. This pressure-voltage transducer is disposed on a supporting plate and at least partially embedded in a sound-insulating, substantially incompressible material, for example a gel. The supporting plate rests herein in contact on a body part, for example a jaw or skull bone, of a person. If this person conducts a conversation, the vibrations of the bone generated through the conversation are transmitted to a supporting plate. This supporting plate subsequently transmits the vibrations onto the pressure-voltage transducer, for example a piezoelectric element or an electret element.

Abstract: An audio emitter comprises a support member operable to support a sound emittive material and a sound emittive material carried by the support member. A protective screen has a plurality of apertures formed therein, the protective screen being spaced a predetermined distance from the sound emittive material, said predetermined distance being a function of a resonant frequency of the audio emitter.

Abstract: An apparatus comprising a combination of a microphone and a composite acoustic panel. The composite acoustic panel comprises materials having different spectra of acoustic absorption. The materials may be integrated in a single layer or in a plurality of different layers.

Abstract: A front resonator for a speaker of a wireless device, comprising: an enclosure mounted over the speaker and forming with an upper surface of the speaker a front volume for the front resonator; and, a horizontal or approximately horizontal tube formed or mounted on a surface of the enclosure, the tube coupled to the front volume, and the tube having at least one end to emit sound generated by the speaker and passing through the front volume and tube from the wireless device.

Abstract: An enclosure with a substantial rectangular configuration, adapted to contain an apparatus sensitive to acoustic vibrations, the enclosure comprising walls and acoustic damping material located within the wall, wherein the acoustic damping material comprises at least one absorbing body of acoustic energy absorbing material located adjacent to a rib of the enclosure. The acoustic vibrations most disturbing the processes in the apparatus within the enclosure are caused by standing acoustic waves within the enclosure with frequencies in the range between 50 Hz and 1000 Hz. These acoustic waves are efficiently damped by the provision of a block of acoustic absorbing material adjacent to one of the ribs of the enclosure, to such an extent that the need for thick walls of the enclosure is substantially obviated, leading to a less voluminous enclosure.

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 audio device is provided with a plurality of Helmholtz resonators. Whereas a cross-sectional area of a neck and a volume of a cavity communicating with the neck are same between at least two of the Helmholtz resonators, a ratio of minimum and maximum values of distances between a center of gravity of the cross section of the neck and individual points defining an outer periphery of the cross section is different between said at least two of the Helmholtz resonators.

Abstract: An in-ear headphone has a shell, a loudspeaker accommodated in a space of the shell for making sound, an ear cushion fixed on a supporting portion of the shell. A through channel passes the whole supporting portion for connecting the space with outside to transmit the sound produced by the loudspeaker. The ear cushion has a through hole passing through the whole ear cushion. A top of the through hole is enlarged to form a first receiving cavity for receiving a first damper. The first damper can seal against the outside region preventing the particles into the in-ear headphone and damaging the loudspeaker. Also, the first damper adjusts the sound effect of the in-ear headphone. Moreover, the first damper can be taken off the first receiving cavity easily and replaced by another one. So, the user can experience varies sound effect by changing the first damper.

Abstract: An audio source tracking arrangement, integrated in or connected to a video conference system, for determining a position of a source creating a sound, including: at least an audio signal processing module configured to determine the position of the source creating the sound based on a plurality of audio signals originating from the source respectively captured by a plurality of microphones; and one or more microphone housings, respectively encapsulating at least one of the plurality of microphones, the one or more microphone housings including a cavity in which at least one of the plurality of microphones is localized, an aperture on a surface of the microphone housing, and a channel extending from the cavity to the aperture, wherein the channel and the cavity are dimensioned to form an acoustical amplifier with a frequency response having one or more high frequency peaks in a frequency band of the sound.

Abstract: A front resonator for a speaker of a wireless device, comprising: an enclosure mounted over the speaker and forming with an upper surface of the speaker a front volume for the front resonator; and, a horizontal or approximately horizontal tube formed or mounted on a surface of the enclosure, the tube coupled to the front volume, and the tube having at least one end to emit sound generated by the speaker and passing through the front volume and tube from the wireless device.

Abstract: A drive cone 11 and a diaphragm 14 are integrally driven by a voice coil 6 movably disposed in a magnetic gap 5. Peripheral edge portions of the drive cone 11 and the diaphragm 14 are supported by a frame 12 via different edge portions 13 and 15, respectively. The drive cone 11 is provided with a rising-up portion 11a which rises up toward an acoustic radiation direction from a inner circumferential end, and a rising-down portion 11b which rises down toward a direction reverse to the acoustic radiation direction. An inner circumferential edge of the diaphragm 14 is fixed at an annular top formed between the rising-up portion and the rising-down portion. Moreover, a first rib 11c and a second rib 11d are formed on the drive cone 11 in such a manner as to rise up toward the acoustic radiation direction integrally with the drive cone. The diaphragm 14 is supported also at the tips of the ribs.

Abstract: A voice coil 6 is movably disposed in a magnetic gap 5. A drive cone (first diaphragm) 11 and a diaphragm (second diaphragm) 14 are integrally driven by the voice coil 6. Peripheral edge portion of the drive cone 11 and the diaphragm 14 are supported by a frame 12 through edge portions 13 and 15, respectively. An annular adhesive receiver 8 is disposed in a peripheral surface of a voice coil bobbin 7 around which the voice coil 6 is wound, and an inner peripheral edge 11a of the drive cone 11 is accommodated in the adhesive receiver 8. The drive cone 11, the adhesive receiver 8 and the voice coil bobbin 7 are connected to each other by an adhesive filled into the adhesive receiver 8.

Abstract: A first electro-acoustic transducer and a second electro-acoustic transducer are supported by a housing attached to a baffle to form an asymmetric acoustical system. An equalizer receives an input signal and generates an equalized signal which is transmitted to the second electro-acoustic transducer. The equalizer is configured to generate the equalized signal such that a net mechanical force acting on the baffle, generated by the first electro-acoustic transducer in response to the input signal and by the second electro-acoustic transducer in response to the equalized signal, is less than the net mechanical force that would be generated if the equalized signal were unchanged in magnitude and equal or opposite in phase to the input signal.

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: In a low frequency transducer system a multi-compression chamber, 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 film-type audio output apparatus includes an audio output device, at least one speaker unit, and at least one film. The at least one speaker unit is positioned at any side of the audio output device. The speaker unit can be an embedded speaker unit. The at least one film can be positioned at any or more places of an inner side and an outer side of the audio output device. When the speaker unit of the audio output device releases sound, the film positioned on the audio output device can get vibration of the sound so that the inside of the audio output device can generate resonance. Thus, the audio output apparatus can generate softer undertone and wider diapason.

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: In a bass reflex type speaker, a Helmholtz resonator is formed by a bass reflex port and a space within a speaker enclosure excluding the bass reflex port and a speaker unit. The bass reflex port of the bass reflex type speaker is movable toward and away from a side surface while maintaining its projecting direction within the speaker enclosure. In response to such movement of the bass reflex port, relative positional relationship between a neck and cavity of the bass reflex type speaker varies.

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 unit is attached to an opening section formed on an front surface of a cabinet. In an inside of the cabinet, fibrous activated carbon (activated carbon fiber) is located. A pressure change in the inside of the cabinet, which changes according to a sound pressure of the speaker unit, is suppressed by physical adsorption by the activated carbon. Further, since the activated carbon fiber has micro pores, which physically adsorbs a gaseous body, situated on a surface of the fiber, a loss in acoustic energy at the time of physical adsorption is small, and thus it is possible to prevent deterioration in a sound pressure level.

Abstract: An acoustic system includes a receiver or microphone, a tube, a barrier, and an equalization device. The receiver is capable of outputting an audio signal. The tube is in connection with the receiver and the audio signal travels along a length of the tube. The barrier is fitted along the tube and the barrier prevents moisture from passing along the tube toward the receiver. The barrier causes an amount of damping to the audio signal. The equalization device is in connection with the receiver and the equalization device counteracts the damping by the barrier. The barrier is configured to have a submersion rating greater than or equal to 7 IP.

Abstract: Systems, methods, and devices for improving speaker performance with an acoustic damped port are disclosed. In accordance with various embodiments of the present invention, a damping material is placed around a vented frame of a speaker driver, and substantially covers or fills the vents of the frame. In some embodiments, the damping material results in improved impedance matching with acoustic delay, without required dimensional tuning (as with conventional ports). In some embodiments, it also reduces the air velocity gradients minimizing higher order frequency distortion components. In some embodiments, the damping material also acts as an absorber of energy by coupling to the sound wave. In some embodiments, low-frequency performance is improved in a small-scale design.

Abstract: Systems, methods, and devices for improving speaker performance with an acoustic damped port are disclosed. In accordance with various embodiments of the present invention, a damping material is placed around a vented frame of a speaker driver, and substantially covers or fills the vents of the frame. In some embodiments, the damping material results in improved impedance matching with acoustic delay, without required dimensional tuning (as with conventional ports). In some embodiments, it also reduces the air velocity gradients minimizing higher order frequency distortion components. In some embodiments, the damping material also acts as an absorber of energy by coupling to the sound wave. In some embodiments, low-frequency performance is improved in a small-scale design.

Abstract: Disclosed is a loudspeaker assembly incorporating innovations resulting in an enclosure of very small volume to which is integrated a large area, shallow and lightweight acoustic diaphragm assembly capable of a natural resonant frequency of a few Hertz. This is achieved by incorporating a vacuum chamber in conjunction with a chamber containing compressed gas or vapor that acts against a movable pressure boundary of changeable area being mechanically coupled with the acoustic radiating diaphragm. In an alternative operating mode, the apparatus also serves as a passive low frequency acoustic attenuator.

Abstract: A loudspeaker box comprising a first and a second speaker unit each adjacent a sound space formed in the housing. The loudspeaker box further comprises a separation element provided between the sound spaces. The separation element comprises faces to reflect at least a part of sound waves to be radiated by a backside of the speaker units into the sound spaces. As well, the separation element leaves open a passage between the sound spaces. By reflection of sound waves at the faces of the separation element an acoustic influence on the speaker units occurs as a result of which for example an electric filtering of signals being supplied to the speaker units can be dispensed with. In a further aspect of the invention, the loudspeaker box comprises a further compartment that is at least partially filled with a granular material.

Abstract: An improved wireless communications earplug for use with a magnetic field transmitter. The wireless earplug has a receiver made of a coil of wire on a magnetic bobbin, mounted in close proximity or in contact with a magnetic case of a speaker. The magnetic case of the speaker serves to increase the magnetic flux through the receiver and improves the efficiency of the earplug. The speaker is acoustically coupled to an eartip, and the earplug may be molded into a custom earplug body.

Abstract: Micro-speaker assemblies and mobile terminals including micro-speaker assemblies are provided. The micro-speaker assemblies include a micro-speaker positioned in a housing. A first forward tuning volume is positioned adjacent a front face of the micro-speaker. A passageway extends from the first forward tuning volume to an opening in the housing. A second forward tuning volume in fluid communication with the passageway is positioned at a location between the first forward tuning volume and the opening in the housing. The second forward tuning volume, the first forward tuning volume and the passageway define a double-resonator that tunes a frequency response of the micro-speaker. Methods for tuning micro-speakers 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.

Abstract: In order to divide the inside space of the cabinet into at least two with a speaker being the center, obtain a plurality of emitted sound energies through openings constructed in each divided sphere, and utilize a cabinet of a loudspeaker apparatus as a sound echo box, a partition wall 4 is disposed at a right angle to a baffle board 2 or a front board 7, passing through the center O of a speaker 3 disposed on the baffle board 2 or the front board 7 of the cabinet 6, and divides the inside space of the cabinet 6 into at least two of an upper chamber 11U and a lower chamber 11D, so that sound energies are emitted from openings 8 and 9 which are provided in each chamber of 11D and 11U, respectively.

Abstract: A resonator for a transducer of an electronic device is provided. The resonator comprises: a first enclosure having a first opening to receive a back end of the transducer and a second opening; and a port connected to the first enclosure through the second opening of the enclosure, the port having a first end, a second end, an interior channel spanning from the first end to the second end. When the transducer is mounted into the first enclosure, a first volume between the transducer and the enclosure is formed which is in communication with air surrounding the second end of the port through the interior channel of the port. A second enclosure to cover a front portion of the transducer may be provided.

Abstract: An acoustic structure and a method for dampening sound. The acoustic structure includes an acoustic absorber having one or more acoustic elements. The acoustic absorber is disposed inside a volume. The acoustic structure further includes an acoustic radiator having one or more acoustic elements. The acoustic radiator is disposed outside the volume. A cross-sectional area of the one or more acoustic elements decreases with a distance from a mouth of the one or more acoustic elements to a throat of the one or more acoustic elements. The acoustic structure also includes one or more acoustic waveguide ducts configured to acoustically couple the acoustic absorber and the acoustic radiator.