Abstract: Systems and methods for active noise cancellation are provided. An example method includes receiving at least two reference signals associated with at least two reference positions. Each of the at least two reference signals includes at least one captured acoustic sound representing an unwanted noise. The reference signals are filtered by individual filters to obtain filtered signals. The filtered signals are combined to obtain a feedforward signal. The feedforward signal is played back to reduce the unwanted noise at a pre-determined space location. The individual filters are determined based on linear combinations of at least two transfer functions. Each of the at least two transfer functions is associated with one of the reference positions. In certain embodiments, the at least two reference signals are captured by at least two feedforward microphones.

Abstract: Systems and methods for active noise cancellation are provided. An example method includes receiving at least two reference signals associated with at least two reference positions. Each of the at least two reference signals includes at least one captured acoustic sound representing an unwanted noise. The reference signals are filtered by individual filters to obtain filtered signals. The filtered signals are combined to obtain a feedforward signal. The feedforward signal is played back to reduce the unwanted noise at a pre-determined space location. The individual filters are determined based on linear combinations of at least two transfer functions. Each of the at least two transfer functions is associated with one of the reference positions. In certain embodiments, the at least two reference signals are captured by at least two feedforward microphones.

Abstract: Systems and methods for acoustic echo cancellation are provided. An example method includes receiving a reference signal. The reference signal represents at least one sound captured inside an enclosure of a loudspeaker. The loudspeaker is operable to play back a far end signal. The method also includes receiving an acoustic signal. The acoustic signal represents at least one sound captured outside the enclosure of the loudspeaker. The acoustic signal includes at least a near end signal and the far end signal. The method enables attenuation, using the reference signal, the far end signal in the acoustic signal. The reference signal can be captured by a low sensitivity microphone placed inside the enclosure of the loudspeaker. The attenuation of the far end signal may include subtractive cancellation.

Abstract: An acoustic transducer comprises one or more electromagnetic motors that drive one or more sets of multiple diaphragms to provide acoustically efficient loudspeaker systems having dimensions that allow use in applications that would be difficult or impossible with traditional transducers. The diaphragms may be driven directly, inertially or fluidically. If diaphragms are driven by rods that pass through holes in the diaphragms, noise may be generated by air that leaks through the pass-through holes. This noise may be reduced or eliminated by measures that reduce or eliminate the air leakage.

Abstract: Systems and methods for acoustic echo cancellation are provided. An example method includes receiving a reference signal. The reference signal represents at least one sound captured inside an enclosure of a loudspeaker. The loudspeaker is operable to play back a far end signal. The method also includes receiving an acoustic signal. The acoustic signal represents at least one sound captured outside the enclosure of the loudspeaker. The acoustic signal includes at least a near end signal and the far end signal. The method enables attenuation, using the reference signal, the far end signal in the acoustic signal. The reference signal can be captured by a low sensitivity microphone placed inside the enclosure of the loudspeaker. The attenuation of the far end signal may include subtractive cancellation.

Abstract: An acoustic transducer includes a housing, a plurality of diaphragms suspended from the housing and separated into one or more groups, and one or more motors combined with the housing that operate in response to an electrical signal. The diaphragms of each group are driven by a respective motor to which all the diaphragms in the group are coupled and at least one motor has an indirect coupling with no direct mechanical connection to the diaphragms driven thereby. One or more electromagnetic motors that drive one or more sets of multiple diaphragms to provide acoustically efficient loudspeaker systems having dimensions that allow use in applications that would be difficult or impossible with traditional transducers.

Abstract: An acoustic transducer comprises one or more electromagnetic motors that drive one or more sets of multiple diaphragms to provide acoustically efficient loudspeaker systems having dimensions that allow use in applications that would be difficult or impossible with traditional transducers. The diaphragms may be driven directly, inertially or fluidically. If diaphragms are driven by rods that pass through holes in the diaphragms, noise may be generated by air that leaks through the pass-through holes. This noise may be reduced or eliminated by measures that reduce or eliminate the air leakage.

Abstract: An acoustic transducer includes a housing, a plurality of diaphragms suspended from the housing and separated into one or more groups, and one or more motors combined with the housing that operate in response to an electrical signal. The diaphragms of each group are driven by a respective motor to which all the diaphragms in the group are coupled and at least one motor has an indirect coupling with no direct mechanical connection to the diaphragms driven thereby. One or more electromagnetic motors that drive one or more sets of multiple diaphragms to provide acoustically efficient loudspeaker systems having dimensions that allow use in applications that would be difficult or impossible with traditional transducers.

Abstract: An acoustic transducer comprises one or more electromagnetic motors that drive one or more sets of multiple diaphragms to provide acoustically efficient loudspeaker systems having dimensions that allow use in applications that would be difficult or impossible with traditional transducers. The diaphragms may be driven directly, inertially or fluidically. If diaphragms are driven by rods that pass through holes in the diaphragms, noise may be generated by air that leaks through the pass-through holes. This noise may be reduced or eliminated by measures that reduce or eliminate the air leakage.

Abstract: An acoustic transducer comprises one or more electromagnetic motors that drive one or more sets of multiple diaphragms to provide acoustically efficient loudspeaker systems having dimensions that allow use in applications that would be difficult or impossible with traditional transducers. The diaphragms may be driven directly, inertially or fluidically. If diaphragms are driven by rods that pass through holes in the diaphragms, noise may be generated by air that leaks through the pass-through holes. This noise may be reduced or eliminated by measures that reduce or eliminate the air leakage.

Abstract: Acoustical characteristics of rooms or other environments in which audio systems operate may be improved by equalization derived from measures of relative acoustic energy storage of the audio system such as a Relative Acoustic-energy Decay Spectrum (RADS). A RADS may be calculated from a measure of absolute energy storage such as RT60 values obtained from models or measurements of the audio system, and normalized with respect to a measure of acoustic energy storage of a reference system.