Abstract: A transition between a stereophonic presentation and a monophonic presentation of a stereophonic input signal that includes a left channel signal and a right channel signal extracts content that is present at similar levels but not in-phase between the left and right channel signals to produce at least one of a left enhancement signal and a right enhancement signal. The left channel signal, the right channel signal, and only one of the left and right enhancement signals are combined to produce a monophonic signal for the monophonic presentation. Cross-fading between the left channel signal and the monophonic signal and between the right channel signal and the monophonic signal may be used to transition between the stereophonic presentation and the monophonic presentation. The stereophonic input signal may be up-mixed to produce enhancement signal. A similar transition between a multichannel presentation and a monophonic presentation of a multichannel signal is described.

Abstract: An audio system includes one or more loudspeaker cabinets, each having loudspeakers. Sensing logic determines an acoustic environment of the loudspeaker cabinets. The sensing logic may include an echo canceller. A low frequency filter corrects an audio program based on the acoustic environment of the loudspeaker cabinets. The system outputs an omnidirectional sound pattern, which may be low frequency sound, to determine the acoustic environment. The system may produce a directional pattern superimposed on an omnidirectional pattern, if the acoustic environment is in free space. The system may aim ambient content toward a wall and direct content away from the wall, if the acoustic environment is not in free space. The sensing logic automatically determines the acoustic environment upon initial power up and when position changes of loudspeaker cabinets are detected. Accelerometers may detect position changes of the loudspeaker cabinets.

Abstract: A binaural sound reproduction system, and methods of using the binaural sound reproduction system to dynamically re-center a frame of reference for a virtual sound source, are described. The binaural sound reproduction system may include a reference device, e.g., a mobile device, having a reference sensor to provide reference orientation data corresponding to a direction of the reference device, and a head-mounted device, e.g., headphones, having a device sensor to provide device orientation data corresponding to a direction of the head-mounted device. The system may use the reference orientation data to determine whether the head-mounted device is being used in a static or dynamic use case, and may adjust an audio output to render the virtual sound source in an adjusted source direction based on the determined use case. Other embodiments are also described and claimed.

Abstract: An audio system embodiment includes a loudspeaker cabinet having at least one loudspeaker transducer and defining a longitudinal axis. Several microphones are distributed around the longitudinal axis, defining an array of microphones. A reference microphone is positioned in the loudspeaker cabinet, e.g., in a rear chamber of the at least one loudspeaker transducer. The audio system includes a processor and a memory having instructions that, when executed by the processor, cause the audio system to receive an audio signal from each distributed microphone and the reference microphone, and therefrom to estimate a direction, relative to the plurality of microphones, of a nearby, acoustically reflective surface. Responsive to the estimated direction, the audio system affects a mode of operation, e.g., beam forms an audio output in a selected direction corresponding to the estimated direction of the acoustically reflective surface. Related principles are described by way of reference to exemplary embodiments.

Abstract: An audio system includes one or more loudspeaker cabinets, each having loudspeakers. The system outputs an omnidirectional sound pattern to determine the acoustic environment. Sensing logic determines an acoustic environment of the loudspeaker cabinets. The sensing logic may include an echo canceller. A playback mode processor adjusts an audio program according to a playback mode determined from the acoustic environment of the audio system. The system may produce a directional pattern superimposed on an omnidirectional pattern, if the acoustic environment is in free space. The system may aim ambient content toward a wall and direct content away from the wall, if the acoustic environment is not in free space. The sensing logic automatically determines the acoustic environment upon initial power up and when position changes of loudspeaker cabinets are detected. Accelerometers may detect position changes of the loudspeaker cabinets.

Abstract: A coil assembly is coupled to a diaphragm. The coil assembly has a number of coils that are fixed in a stacked, end to end manner along a length axis. The coils include a middle coil, a several upper coils and several lower coils. Each coil has a respective pair of coil terminals so that it can be independently driven by an audio signal. The coil assembly as a whole is overhung, while each of constituent coils is underhung so that there are at least two adjacent coils that are completely within the magnetic gap, and at least two other coils that are completely outside the magnetic gap, during a majority of the full excursion of the coil assembly. Other embodiments are also described and claimed.

Abstract: A coil assembly is coupled to a diaphragm. The coil assembly has a number of coils that are fixed in a stacked, end to end manner along a length axis. The coils include a middle coil, a several upper coils and several lower coils. Each coil has a respective pair of coil terminals so that it can be independently driven by an audio signal. The coil assembly as a whole is overhung, while each of constituent coils is underhung so that there are at least two adjacent coils that are completely within the magnetic gap, and at least two other coils that are completely outside the magnetic gap, during a majority of the full excursion of the coil assembly. Other embodiments are also described and claimed.

Abstract: An audio system embodiment includes a loudspeaker cabinet having at least one loudspeaker transducer and defining a longitudinal axis. Several microphones are distributed around the longitudinal axis, defining an array of microphones. A reference microphone is positioned in the loudspeaker cabinet, e.g., in a rear chamber of the at least one loudspeaker transducer. The audio system includes a processor and a memory having instructions that, when executed by the processor, cause the audio system to receive an audio signal from each distributed microphone and the reference microphone, and therefrom to estimate a direction, relative to the plurality of microphones, of a nearby, acoustically reflective surface. Responsive to the estimated direction, the audio system affects a mode of operation, e.g., beam forms an audio output in a selected direction corresponding to the estimated direction of the acoustically reflective surface. Related principles are described by way of reference to exemplary embodiments.

Abstract: A method for using a loudspeaker array that is housed in a loudspeaker cabinet to present audio content to a listener in a room includes receiving (1) an audio channel that includes audio content and (2) acoustical characteristics of the room. The method also produces (1) a first beamformer input signal from the audio channel and (2) a second beamformer input signal and a third beamformer input signal by decorrelating the audio channel and adjusting the audio channel in accordance with the acoustical characteristics of the room. The second and third beamformer input signals are different de-correlated versions of the audio channel. The method also generates driver signals from the first, second, and third beamformer input signals to drive the loudspeaker array to produce a main beam, a first ambient beam, and a second ambient beam, respectively. Other embodiments are also described and claimed.

Abstract: An audio system includes one or more loudspeaker cabinets, each having loudspeakers. Sensing logic determines an acoustic environment of the loudspeaker cabinets. The sensing logic may include an echo canceller. A low frequency filter corrects an audio program based on the acoustic environment of the loudspeaker cabinets. The system outputs an omnidirectional sound pattern, which may be low frequency sound, to determine the acoustic environment. The system may produce a directional pattern superimposed on an omnidirectional pattern, if the acoustic environment is in free space. The system may aim ambient content toward a wall and direct content away from the wall, if the acoustic environment is not in free space. The sensing logic automatically determines the acoustic environment upon initial power up and when position changes of loudspeaker cabinets are detected. Accelerometers may detect position changes of the loudspeaker cabinets.

Abstract: A loudspeaker cabinet has a number of pairs of microphones, each pair includes the same internal microphone and a different external microphone. For each pair of microphones, a process (i) receives a first audio signal of sound captured by the internal microphone and a second audio signal of sound captured by the different external microphone, (ii) estimates, using first and second audio signals, a radiation impedance, and (iii) computes a detection value based on the radiation impedance in a frequency band. A difference between (i) a currently computed detection value associated with a given pair of microphones and (ii) a previously computed detection value associated with said given pair, is computed. The sound produced by the cabinet is adjusted, in response to the computed difference meeting a threshold. Other embodiments are also described and claimed.

Abstract: An audio system includes one or more loudspeaker cabinets, each having loudspeakers. The system outputs an omnidirectional sound pattern to determine the acoustic environment. Sensing logic determines an acoustic environment of the loudspeaker cabinets. The sensing logic may include an echo canceller. A playback mode processor adjusts an audio program according to a playback mode determined from the acoustic environment of the audio system. The system may produce a directional pattern superimposed on an omnidirectional pattern, if the acoustic environment is in free space. The system may aim ambient content toward a wall and direct content away from the wall, if the acoustic environment is not in free space. The sensing logic automatically determines the acoustic environment upon initial power up and when position changes of loudspeaker cabinets are detected. Accelerometers may detect position changes of the loudspeaker cabinets.

Abstract: A loudspeaker cabinet has a number of pairs of microphones, each pair includes the same internal microphone and a different external microphone. For each pair of microphones, a process (i) receives a first audio signal of sound captured by the internal microphone and a second audio signal of sound captured by the different external microphone, (ii) estimates, using first and second audio signals, a radiation impedance, and (iii) computes a detection value based on the radiation impedance in a frequency band. A difference between (i) a currently computed detection value associated with a given pair of microphones and (ii) a previously computed detection value associated with said given pair, is computed. The sound produced by the cabinet is adjusted, in response to the computed difference meeting a threshold. Other embodiments are also described and claimed.

Abstract: An audio system includes an external microphone to receive a near-end audio content and a loudspeaker transducer and a corresponding enclosure defining an acoustic chamber. An internal pressure-gradient microphone is positioned in the acoustic chamber to detect a radiated output from the loudspeaker transducer. The audio system also includes a processor and a memory having instructions that, when executed by the processor, cause the audio system to receive a near-end signal from the external microphone and a reference signal from the internal microphone. The instructions, when executed, further cause the processor to cause the audio system to filter the reference signal from the near-end signal to define a clean near-end signal, and to emit the clean near-end signal. Related principles are described by way of reference to method and apparatus examples.

Abstract: A system and method are described for transforming stereo signals into mid and side components xm and xs to apply processing to only the side-component xs and avoid processing the mid-component. By avoiding alteration to the mid-component XM, the system and method may reduce the effects of ill-conditioning, such as coloration that may be caused by processing a problematic mid-component xM while still performing crosstalk cancellation and/or generating virtual sound sources. Additional processing may be separately applied to the mid and side components xM and xs and/or particular frequency bands of the original stereo signals to further reduce ill-conditioning.

Abstract: A binaural sound reproduction system, and methods of using the binaural sound reproduction system to dynamically re-center a frame of reference for a virtual sound source, are described. The binaural sound reproduction system may include a head-mounted device, e.g., headphones, having a device sensor to provide device orientation data corresponding to a direction of the head-mounted device. The system may use the orientation data to determine whether the head-mounted device has moved over an angle within a range of movement, and may adjust an audio output to render the virtual sound source in an adjusted source direction based on the range of movement. Other embodiments are also described and claimed.

Abstract: A method for using a loudspeaker array that is housed in a loudspeaker cabinet to present audio content to a listener in a room includes receiving (1) an audio channel that includes audio content and (2) acoustical characteristics of the room. The method also produces (1) a first beamformer input signal from the audio channel and (2) a second beamformer input signal and a third beamformer input signal by decorrelating the audio channel and adjusting the audio channel in accordance with the acoustical characteristics of the room. The second and third beamformer input signals are different de-correlated versions of the audio channel. The method also generates driver signals from the first, second, and third beamformer input signals to drive the loudspeaker array to produce a main beam, a first ambient beam, and a second ambient beam, respectively. Other embodiments are also described and claimed.

Abstract: A loudspeaker cabinet has a number of pairs of microphones, each pair includes the same internal microphone and a different external microphone. For each pair of microphones, a process (i) receives a first audio signal of sound captured by the internal microphone and a second audio signal of sound captured by the different external microphone, (ii) estimates, using first and second audio signals, a radiation impedance, and (iii) computes a detection value based on the radiation impedance in a frequency band. A difference between (i) a currently computed detection value associated with a given pair of microphones and (ii) a previously computed detection value associated with said given pair, is computed. The sound produced by the cabinet is adjusted, in response to the computed difference meeting a threshold. Other embodiments are also described and claimed.

Abstract: A differential pressure gradient micro-electro-mechanical system (MEMS) microphone for measuring an acoustic characteristic of a loudspeaker. The microphone includes a MEMS microphone housing and a compliant membrane mounted in the MEMS microphone housing, the compliant membrane dividing the MEMS microphone housing into a first chamber and a second chamber. The first chamber includes a primary port open to a first side of the compliant membrane and the second chamber includes a secondary port open to a second side of the compliant membrane, and the primary port and the secondary port are tuned with respect to one another to control a pressure difference between the first side and the second side of the compliant membrane such that at least 10 dB of attenuation is observed in a microphone signal output relative to a microphone having a sealed first or second chamber.

Abstract: A process for reproducing sound using a loudspeaker array that is housed in a loudspeaker cabinet includes the selection of a number of sound rendering modes and changing the selected sound rendering mode based on changes in one or both of sensor data and a user interface selection. The sound rendering modes include a number of mid-side modes and at least one direct-ambient mode. Other embodiments are also described and claimed.