Abstract: A compression driver includes a dome diaphragm having a convex surface and a concave surface and a phasing plug having a base portion with a first side and an opposed second side. The base portion first side is disposed adjacent the convex surface of the diaphragm and defines a compression chamber therebetween. The base portion includes a plurality of channels that extend therethrough from the first side to the second side for sound waves to travel through the base portion, the plurality of channels converging to form an annular exit of the compression driver.

Abstract: An acoustic waveguide in accordance with one or more embodiments of the present technology that comprises a housing having a proximal end with an inlet aperture and a distal end with an outlet aperture, and a mounting flange positioned at the proximal end and configured to acoustically couple a driver to inlet aperture. A plurality of sound channels extend through the housing and acoustically couple the inlet aperture to the outlet aperture. Each sound channel at least partially defining a sound path has an acoustic length, wherein at least one of the sound paths of the plurality of sound channels has a bend angle that exceeds 180 degrees.

Abstract: An acoustic waveguide in accordance with one or more embodiments of the present technology that comprises a housing having a proximal end with an inlet aperture and a distal end with an outlet aperture, and a mounting flange positioned at the proximal end and configured to acoustically couple a driver to inlet aperture. A plurality of sound channels extend through the housing and acoustically couple the inlet aperture to the outlet aperture. Each sound channel at least partially defining a sound path has an acoustic length, wherein at least one of the sound paths of the plurality of sound channels has a bend angle that exceeds 180 degrees.

Abstract: The invention relates to a sound broadcasting device comprising a high-frequency section including at least one high-frequency acoustic source (SHF), and a medium-frequency section including at least two medium-frequency sources (SMF), the acoustic sources (SHF, SMF) being vertically superposed, where the medium-frequency section comprises a lower sub-section, arranged below the high-frequency section and comprising at least one medium-frequency acoustic source (SMF), and an upper sub-section, arranged above the high-frequency section and comprising at least one medium-frequency acoustic source (SMF), where the vertical directivity of the high-frequency section has an incline, relative to the horizontal (H), that is substantially equal to the incline (?MF) of the vertical directivity of the medium-frequency section relative to the horizontal (H), so that the overall vertical directivity of the device has a non-zero incline (?Dir) relative to the horizontal (H).

Abstract: An acoustic meta material (AMM) spiral device for passive amplification of sound is described. The AMM amplifier device employs at least one deep sub-wavelength spiral design with high refraction index, based on an exponential spiral shape. The AMM spiral amplifier is used to focus on low frequency sound amplification and to cover broadband frequency range. Sound emanating from a speaker travels into a spiral channel until reaching the apex of the spiral. When twin spirals are used, the sound then enters a second spiral for radiating into open air.

Abstract: A speaker cabinet to effectively amplify an acoustic guitar, comprising of: two chambers, two speaker drivers, a port, and a tube within the port. One speaker driver is mounted onto front of tube to radiate sound outwards, while the rear sound waves radiate through same tube into ported resonant chamber. The second chamber is sealed, is next to ported chamber, and utilizes a second speaker driver. The front sound waves of second driver radiant into ported resonant chamber, while the rear waves radiate into the sealed chamber. The two distinct sound waves now inside ported chamber mix with each other, then flow around the tube and through the port. All three sound waves mix in front of the cabinet. Other embodiments include: Sound deflectors, horn-loading the port, a passive radiator on the sealed chamber to radiate a fourth sound wave, and a guitar shape inside the ported resonant chamber.

Abstract: A coaxial loudspeaker apparatus (10) comprising: a first unit, being arranged to propagate sound in a first frequency range; a second unit, being arranged to propagate sound in a second frequency range that is higher than the first frequency range, comprising a first waveguide (30); a second waveguide (60) arranged to extend substantially in prolongation of the first waveguide (30); and a third waveguide (100) arranged to extend substantially in prolongation of the second waveguide (60).

Abstract: Embodiments are disclosed for a loudspeaker for producing directed acoustic vibrations. In some embodiments, a loudspeaker includes an electromagnetic transducer including diaphragm configured to generate acoustic vibrations. The loudspeaker may further include an aperture positioned in front of the diaphragm in a direction of propagation of the acoustic vibrations, the aperture including an opening having one or more protrusions forming an opening shape having non-uniform edges.

Abstract: An acoustic transducer may comprise a sound source, a throat connected to the sound source, and a horn connected to the throat. The horn may be arranged on a wall, wherein the throat is designed such that a path of the sound from the sound source to an interface between the throat and the horn is shorter in a region close to the wall than at a region that is remote from the wall.

Abstract: A SONAR system for use with a robotic vacuum having SONAR emitters and receivers thereon. The SONAR system comprises a waveguide or horn located in front of the emitters and receivers that can improve the overall target resolution and reduce the number of “dead zones” where targets are not easily resolved.

Abstract: A loudspeaker assembly comprises a casing with a diaphragm loudspeaker mounted in the casing. A phase plug is mounted in the casing adjacent the diaphragm loudspeaker. The phase plug has a central cone with a longitudinal axis extending from an input end adjacent the diaphragm loudspeaker to an output end with its base at the input end tapering to an apex at the output end. A plurality of vanes extend radially outwardly from the central cone with the plurality of vanes being thickest at the input end and progressively thinning toward the output end. Radially outward edges of the plurality of vanes are twisted relative to the longitudinal axis with the degree of twist being progressively greater with increasing proximity to the output end. The plurality of vanes tapers in width along their longitudinal extent from the input end to the output end.

Abstract: A speaker includes a ring-shaped vibrating member fixed to an internal support body at an internal peripheral edge, and a bobbin attached to an external peripheral edge thereof. A voice coil is attached to the bobbin and is located in a magnetic gap. A ring-shaped control member faces a front portion of the vibrating member, and a sound pass space is formed at an external peripheral side of the control member and at an internal peripheral side thereof. When listening to the speaker from a diagonal location, treble sound waves generated from the left side area are perturbed by the control member so as to prevent interference from sound waves generated from bilaterally separated areas, which prevents a decrease of treble sound pressure levels.

Abstract: A cover for a hand-held device, which has a device body and a speaker, includes a cover body configured for covering a portion the device body and for covering the speaker and a channel for positioning adjacent the device body. The channel is configured to form a sound duct when mounted adjacent the back side of the device body and to be in communication with the speaker when the cover is mounted to the hand-held device for redirecting at least a portion of the sound waves emitted from the speaker to a location remote from the speaker.

Abstract: A system and method for modulating the sound pressure that is output from an audio transducer is disclosed. In one embodiment, the method includes receiving an audio signal and placing the audio signal across a voice coil of the transducer. In addition, a voltage is applied across a field coil of the transducer, the field coil being separate from the voice coil. And the voltage that is applied across the field coil is adjusted so as to modulate the sound pressure output from the audio transducer.

Abstract: An acoustic horn. In one implementation, the horn includes at least four wall sections, defining a passageway. The cross-sectional area of the mouth is at least ten times the cross sectional area of the throat. The wall sections are dimensioned so that at least one wall section has a dimension at the throat at least ten times a dimension at the throat of a second wall section. In another implementation the cross-section at the mouth is elongated and is be bounded by a continuous curve defining a geometric figure having a major axis at least ten times a minor axis.

Abstract: A horn loudspeaker, in particular for reproducing bass sound in public address systems, in which the horn (23) is mounted directly to the driver element (21) without any intervening compression chamber. The back side of the driver element (21) is covered by a back chamber (24) designed with walls of a semi-permeable material. The walls may be perforated or made of a “leaky” material such as cell foam with open structure, or a fibrous material. The “leaky” back chamber will prevent the build up of high pressures in the back chamber at large cone excursions. The horn loudspeaker is suitable for stacking in groups of two or more, so as to produce a sound source scalable for reproducing any frequency range heard by humans in public address systems or hi-fi systems. Due to the back chamber design, the horn loudspeaker, for high frequencies especially in conical horn shaped versions, can be stacked close together.

Abstract: Provided are a sound generation system and a sound recording system, which are placed in a room to adjust sound. A columnar body is disposed around a sound source to adjust how much sound of a low-tone range, as well as of a middle- and high-tone range, is absorbed and diffused. Moreover, a columnar body is disposed around a recording device to adjust how much sound of a low-tone range, as well as of a middle- and high-tone range, is absorbed and diffused. The columnar bodies may be made of a combination of different diameters and/or lengths. The arrangement distances may be random. With the columnar body disposed at the most appropriate location, it is possible to adjust sound in a wide band.

Abstract: A loudspeaker system is provided for uniformly emanating sound waves to a listening area. The loudspeaker system includes a plurality of drivers, where each driver includes a front face, a rear face, and an axis of symmetry extending substantially perpendicularly through both the front and rear face. Each driver is configured to emanate low and high frequency sound waves from its front face substantially along its axis of symmetry. The loudspeaker system also includes a support structure having an inner volume. The support structure is configured to support the drivers in an arrangement such that the front face of each driver is directed toward the inner volume and the axis of symmetry of each driver intersects a relatively small volume near a central point located at the center of the inner volume. A listening area for the loudspeaker system is outside of the inner volume of the support structure.

Abstract: A loudspeaker box (300) has a loudspeaker housing (1) and a sound source (3a) with a non-rotationally symmetrical radiation characteristic. The sound path of the sound source (3a) contains an acoustic element (4) which dilates or constricts the radiation of sound in at least one radiation plane. The loudspeaker box (300) comprises a mechanism which can be used to position the sound source (3a) and the acoustic element (4) in different rotational positions relative to one another.

Abstract: The present invention comprises a loudspeaker system that includes a loudspeaker and a detachable mount. In one or more embodiments, the loudspeaker and mount include electrical connectors that are engaged when the loudspeaker is attached to the mount. In one or more embodiments, the loudspeaker and mount comprise mating mounting structures that support the loudspeaker on the mount when the mounting structure of the loudspeaker is engaged with the mounting structure of the mount. In one or more embodiments, multiple configurations of the mount are provided that allow the loudspeaker to be mounted with a variety of orientations with respect to the mounting surface. In one or more embodiments, the loudspeaker comprises a tweeter with a rotatable wave guide that allows the dispersion angle of the tweeter to be adjusted to accommodate the variety of orientations at which the loudspeaker may be mounted.

Abstract: In a speaker, a space surrounded by a frame on one side of a diaphragm is separated by a damper into a first internal space and a second internal space. The first internal space and the second internal space are caused to face one part and another part of an opening provided in the frame. A duct protrudes from the frame, and the opening is an open end of the duct on the base end side thereof. The speaker is installed, for example, outside a vehicle cabin with the duct inserted into an opening in a vehicle cabin wall, and the first and second internal spaces are caused to communicate with a space in the vehicle cabin through the duct. Therefore, reproduced sound in the bass range having a high sound pressure can be discharged through the duct to the space in the vehicle cabin.

Abstract: A directional waveguide array apparatus can transmit and/or receive airborne or fluid-borne audio with the appropriate selection of transducers. The present invention advances directional waveguide arrays by allowing construction of a directional audio device with desired frequency bandwidths, array patterns, and gain by appropriate geometric configurations of the array of waveguide channel ports, as well as dimensioning and configuration of waveguide channel and chamber parameters. Embodiments of the present invention enable increased immunity to environmental noises, temperature, and humidity; low cost of construction; high reliability; simplicity of operation; very low power consumption; real-time steering of directivity (interference) pattern; wide range of audio powers that can be transmitted or received; and interchangeable transducer types.

Abstract: A horn assembly for high frequency acoustic speakers. In an array of speakers, a spacing between adjacent speakers needs to be less than the wavelength of sound being emitted in order to combine effectively. For high frequency sound, a relatively small wavelength imposes a limitation on such a spacing. Such limitations are sometimes physically difficult to implement. A horn assembly increases the exit dimensions of the small speaker to larger desired dimensions by utilizing one or more plugs that divide a larger horn cavity into smaller horn cavities and creating similar pathlengths thereto. The similar pathlengths and the smaller horn cavities having desired dimensions allow the exiting sound to combine effectively. The overall dimensions of the exit portion of the horn assembly can be selected to match the dimensions of larger bass speakers, thus allowing improved arraying of the high frequency speakers with respect to other larger speakers.

Abstract: An electrostatic loudspeaker (ESL) assembly providing curvature in two directions for improved dispersion of sound waves. The ESL comprises at least one stator panel, a flexible diaphragm and a spacer that impedes contact between the stator panel and the diaphragm. The stator is formed from a material that comprises an array of apertures. Furthermore, the material can be annealed. The material temper, along with the aperture geometry and patter, affect the stretchability of the material. The two-axis curved structure enables a compact form of ESL to be realized, including bookshelf type loudspeakers whereas all known commercial units are comparable in height to that of a human listener. The individual curved ESL panels can also be readily combined to create larger transducer assemblies including omni-directional units.

Abstract: Methods and apparatus are provided for waveguide structures and speaker assemblies. In one embodiment, a waveguide may include an input aperture configured to receive a sound signal from a sound source, and a plurality of isolated sound paths having substantially equal path lengths. Each isolated sound path may be formed within a housing of the waveguide and formed with a curved path to reduce the depth of the waveguide. The waveguide may include a plurality of plugs, wherein each plug divides an output of one of the isolated sound paths into a plurality of output sound paths and defines a plurality of output apertures of the waveguide. Each output sound path is characterized by a reduced width relative to the output of the isolated sound path, the plurality of output apertures configured to output a combined sound signal based, at least in part, on the plurality of sound signals.

Abstract: A loudspeaker assembly, including an acoustic waveguide; an acoustic driver mounted in the waveguide so that a first surface radiates sound waves into the waveguide so that the sound waves are radiated from the waveguide; and an acoustic volume acoustically coupled to the acoustic waveguide for increasing the amplitude of the sound waves radiated from the acoustic waveguide.

Abstract: A flexible multiple speaker support apparatus is provided for supporting a plurality of speakers therein and includes a flexible, hollow speaker support unit which includes a plurality of open, sound emission channels. The speakers are housed within the flexible, hollow speaker support unit, and the speakers are placed in registration with the open, sound emission channels. With one embodiment of the invention, the flexible, hollow speaker support unit includes a flexible, tubular speaker support member, and the flexible, tubular speaker support member includes a plurality of the open, sound emission channels. The speakers are placed in registration with the open, sound emission channels. With another embodiment of the invention, a suspension bracket assembly is connected to the flexible, hollow speaker support unit for supporting the flexible, hollow speaker support unit in a desired orientation from a ceiling, wall or other surface.

Abstract: A receiver or loudspeaker having a plurality of sound generators each having a housing and a sound output. An oblong channel is formed by a channel-forming element and parts of the housings. The sound outputs are positioned on one side of a middle of the channel and a outlet of the channel is positioned on the other side of the middle of the channel so that the channel has a length adapted to acoustically alter the sound. The use of the housings for forming the channels provides a more compact structure.

Abstract: A horn enclosure combines sound output emanating from a plurality of acoustic drivers. The horn enclosure includes a plurality of sound input plenums, a plurality of flow passageways, and a common sound output chamber. Each of the input plenums is coupled to an acoustic driver for receiving generated sound output from the associated driver. A plurality of partitions defining the plurality of flow passageways provides for a plurality of acoustic paths from each acoustic driver and through the input plenum. The common sound output chamber is in acoustic communication with each plenum through respective flow passageways and has a sound output opening for passage of the combined sound output.

Abstract: A docking station for sound amplification and sound quality enhancement is provided. The docking station includes a support structure for holding a mobile terminal having an internal speaker to sustain the posture of the mobile terminal, and a body for supporting the support structure, and for physically contacting the speaker to increase the volume of sound output from the speaker. The body includes a collecting hole for contacting the speaker to collect sound waves, and a guide hole that extends from the collecting hole through the body to the outside along an extension direction, is divided into two branches within the body to guide the collected sound waves along different paths, and has a horn shape whose cross section increases along the extension direction. Hence, the docking station can increase the volume of audible sound and sound quality without separate supply of power.

Abstract: A loudspeaker driver 100 with new horn throat configuration 120 has a phase plug summation plane radius that is also the effective throat of the driver. The selected plane “D” where the elements of the horn that provide directional information to the wave front are implemented is made part of the geometry of the magnetic return circuit back plate 108. The portion of the back plate that is coincident with the selected plane “D” has a lumen or opening that is made equal to the radius of the circle defined by the phase plug summation plane. The geometry of the back plate's lumen controls projected sound's radiation pattern.

Abstract: An audio system for a television using a pipe type passive directional acoustic device mounted in a television cabinet. The slotted pipe type passive directional acoustic device includes a first acoustic driver, acoustically coupled to a pipe to radiate acoustic energy into the pipe. The first pipe includes an elongated opening along at least a portion of the length of the pipe. Acoustically resistive material is in the opening. Pressure waves are radiated to the environment through the opening. The pressure waves are characterized by a volume velocity. The pipe, the opening, and the acoustically resistive material are configured so that the volume velocity is substantially constant along the length of the pipe. The passive directional acoustic devices directionally radiate sound waves laterally from the television cabinet.

Abstract: A sound reproduction system is disclosed in which at least one driver is provided, along with a horn member in acoustic loading relationship to the driver. The horn member defines an internal passageway having a first end and a second open end, with the driver at the first end, producing a driver soundwave having an initial central axis and an initial amplitude distribution. A plurality of vanes are disposed in the internal passageway, at different angles from the central axis to deflect respective portions of the driver soundwave so as to alter the initial amplitude distribution.

Abstract: The present invention is an acoustic traveling wave tube system for propagating a directional acoustic wave comprising an acoustic traveling wave tube having a cylindrical shape with a load on one end of the tube, a plurality of excitation rings positioned around a circumference of the tube and spaced at predetermined intervals along a length of the tube and a microprocessor having a database containing a plurality of waveforms representative of acoustic signals. The microprocessor energizes one of the plurality of excitation rings to form an acoustic wave, sequentially energizes one or more of the remaining excitation rings along the length of the tube to amplify the acoustic wave as the acoustic wave travels along the length of the tube, and propagates the acoustic wave from an end of the tube opposite the load as a shaped directional acoustic wave.

Abstract: A loudspeaker assembly, including an acoustic waveguide; an acoustic driver mounted in the waveguide so that a first surface radiates sound waves into the waveguide so that the sound waves are radiated from the waveguide; and an acoustic volume acoustically coupled to the acoustic waveguide for increasing the amplitude of the sound waves radiated from the acoustic waveguide.

Abstract: An accessory for a portable electronic device having a speaker uses an acoustic wave guide to passively amplify and direct the output of the device's speaker. The accessory has a housing with a docking cavity formed therein. The docking cavity has supportive sidewalls that are adapted to receive and support the portable electronic device in an upright position. A cable access channel is formed in the docking cavity that allows a connector and cable to be coupled to the portable electronic device when the portable electronic device is mounted in the docking cavity. An acoustic waveguide having a spiral shaped acoustic chamber is positioned in the housing such that an entrance to the acoustic waveguide corresponds to a hole in the docking cavity that is positioned to correspond to the location of the speaker of the device when the device is mounted in the docking chamber. The exit of the acoustic chamber corresponds to an exterior opening in a sidewall of the housing and the hole in the docking cavity.

Abstract: A sound reproduction system is disclosed in which a sound barrier defines a horn passageway having a first end and a second open end. A high frequency range driver is provided at the first end, and is mutually coupled with a lower driver to the horn passageway. The lower driver has an upper frequency end lower than a frequency of a first cancellation notch for the drivers. The lower driver is located at a position along the horn passageway at which the passageway has a preselected cross-sectional area which is no greater than an area of a round cross section having a circumference equal to one wavelength at the upper frequency end.

Abstract: For a loudspeaker with a cabinet and a driver cone, an acoustic speaker lens may be positioned on the driver cone. The acoustic speaker lens may include a center post and a plurality of ribs extending radially outward from the center post. The acoustic speaker lens may reduce turbulence in air in front of the loudspeaker, thereby leading to an improved perception of audio reproduction.

Abstract: A woofer-less and box-less loudspeaker system including a plurality of tweeter drivers is provided. The speaker system includes a plurality of drivers, each driver including a front face and a rear face with an axis of symmetry, each driver configured for propagating sound energy along the axis of each driver from the front face, wherein the sound energy includes low frequency and high frequency components; and a support structure for arranging the plurality of drivers in such a way that the axis extending from the rear face of each of the drivers converge in a single point in space, wherein as the sound is propagated along the axis of each driver from the front face, the high frequency components from each driver are evenly spaced and the low frequency components from each driver are reinforced by the low frequency components of adjacent drivers.

Abstract: Disclosed herein is a speaker system unit with a cone type vibration plate, a horn and a diffuser. The horn is disposed such that a small-diameter opening thereof is positioned inward from a front opening of the vibration plate, and an outer surface of the horn is arranged along an inner surface of the vibration plate to form a first acoustic path. The diffuser has a base portion, a front end portion and an outer peripheral surface extending therebetween, and is disposed such that the base portion is positioned inward from a front opening of the horn, opposite the small-diameter opening of the horn. The diffuser has a specific shape such that the outer peripheral surface expands along an inner surface of the horn to form a second acoustic path and then narrows toward the front end portion of the diffuser.

Abstract: A loudspeaker horn includes a pair of opposed flared sides defining a passage diverging to a mouth, and a vane positioned in the passage for steering sound waves through the passage. The vane may have a straight configuration and be either centrally located between the flared sides or laterally offset in the diverging passage. The vane may be fixed in position or, more preferably, be pivotable so as to be adjustable before each new use according to conditions at that use. The horn may be part of a horn unit that includes a funnel for feeding sound to the horn, and the horn or horn unit may be part of a horn loudspeaker.

Abstract: At least one exciter is used to produce sound for a flat panel display. The exciter vibrates the housing for production of sound. The housing may also include a plate mounted on the front surface of the housing and the exciter may be attached to the plate, which serves as a resonance plate.

Abstract: An ear speaker device includes an electroacoustic transducer including a housing mounted at a predetermined position of listener's head, a speaker unit mounted on one surface in the housing, and positioned away from an entrance of the listener's external acoustic meatus for a predetermined distance when the housing is mounted on the listener's head, and a tubular duct extended so as to allow a sound generated by the housing in the inner space thereof to reach the vicinity of the entrance of the listener's external acoustic meatus, and a hole for emitting sound of the duct is oriented to the opposite direction with respect to the entrance of the external acoustic meatus; and a mounting part used for mounting the electroacoustic transducer on the listener's head in a manner that the predetermined distance is provided between the speaker unit and the entrance of the listener's external acoustic meatus.

Abstract: An electroacoustic transducer comprises an electric sound conversion section that vibrates a mechanical device based on an electric signal so as to emit a sound wave; and an electromagnetic wave radiation section that generates and emits an electromagnetic wave from the electrical signal.

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 protective sleeve having a built-in sound-amplifying channel is configured to cover a portable electronic product having an audio port. The protective sleeve includes an accommodating portion and a sound-amplifying channel. The accommodating portion is provided in the protective sleeve for allowing the portable electronic product to be accommodated therein. The sound-amplifying channel is formed in the protective sleeve. One end of the sound-amplifying channel is connected to the audio port, and the other end thereof protrudes from the protective sleeve to form a sound-amplifying section. The sound of the portable electronic product is emitted from the audio port and amplified through the sound-amplifying channel and the sound-amplifying section. Thus, an external loud speaker is unnecessary, and the protective sleeve itself can generate a good sound-amplifying effect, thereby increasing the functionality and practicability thereof greatly.

Abstract: A loudspeaker device includes a loudspeaker box having a space therein, a loudspeaker unit, and a passive radiator. The loudspeaker unit and the passive radiator are attached to the loudspeaker box. The space of the loudspeaker box has a depth smaller on the passive radiator side than on the loudspeaker unit side. This structure allows the loudspeaker device to be mounted on a thin apparatus.

Abstract: A steerable acoustic waveguide apparatus includes plural plates arranged in one or more linear arrays. Steering of an acoustic beam radiated from the waveguide apparatus may be achieved through differential delays of acoustic signals resulting from differences in timing, frequency, or mode or resulting from differences in physical attributes of the plates. In one aspect, where the apparatus is used with a target that is confined by a conduit such as a pipe, a longitudinal plane for the conduit intersects the linear array, an array plane for the linear array has a conduit orientation relative to the longitudinal plane, and the conduit orientation is substantially perpendicular or substantially parallel. The waveguide apparatus may serve as a thermal buffer and may simplify access to an acoustic path in a device such as an ultrasonic flowmeter.

Abstract: A system and method for modulating the sound pressure that is output from an audio transducer is disclosed. In one embodiment, the method includes receiving an audio signal and placing the audio signal across a voice coil of the transducer. In addition, a voltage is applied across a field coil of the transducer, the field coil being separate from the voice coil. And the voltage that is applied across the field coil is adjusted so as to modulate the sound pressure output from the audio transducer.

Abstract: A mobile communication device is provided. The mobile communication device includes a terminal body, and a speaker module located in the terminal body. The speaker module includes an enclosure located in the terminal body, the enclosure defining a chamber therein, and a speaker having a front surface and a rear surface, the speaker being located in the enclosure such that the front surface of the speaker is exposed from the enclosure and the rear surface thereof is positioned within the chamber, to allow a sound generated from the rear surface to resonate within the chamber. A mutual interference between the sound generated from the front side of the sound emission part and the sound emitted from the rear side thereof can be reduced to thereby improve the performance of the middle and low sound.