Abstract: An acoustic chamber includes a loudspeaker, which includes at least two membranes that each reproduce a different frequency band, and a filter that makes it possible to generate a plurality of activation signals from an audio signal source. The activation signals are each applied to an actuator of one of the membranes. The acoustic chamber has an operating range having a variable and controlled directivity, each frequency of which belongs to at least two frequency bands reproduced by the membranes. The acoustic chamber obtains a directivity control signal, and the filter makes it possible to dose, for each frequency of the operating range and depending on the directivity control signal, the contribution of each one of the at least two membranes reproducing the frequency.

Abstract: An acoustic chamber includes a loudspeaker, which includes at least two membranes that each reproduce a different frequency band, and a filter that makes it possible to generate a plurality of activation signals from an audio signal source. The activation signals are each applied to an actuator of one of the membranes. The acoustic chamber has an operating range having a variable and controlled directivity, each frequency of which belongs to at least two frequency bands reproduced by the membranes. The acoustic chamber obtains a directivity control signal, and the filter makes it possible to dose, for each frequency of the operating range and depending on the directivity control signal, the contribution of each one of the at least two membranes reproducing the frequency.

Abstract: The present invention relates to an echo reduction method implemented with a multi-sensor sound pickup device (8) forming an antenna (10), and a sound playback device (13). The method consists in subjecting the output signals ym(t) from the sensors (11m) to complex weights w(f), said weights w(f) being calculated by maximizing the directivity factor Fd(f) under constraints at low frequencies and in the near field. The invention also provides an echo reduction apparatus (6). The apparatus comprises: a multi-sensor sound pickup device (8) forming an antenna (10); means for calculating a first constraint; and means for calculating a second constraint.

Abstract: The present invention relates to an echo reduction method implemented with a multi-sensor sound pickup device (8) forming an antenna (10), and a sound playback device (13). The method consists in subjecting the output signals ym(t) from the sensors (11m) to complex weights w(f), said weights w(f) being calculated by maximizing the directivity factor Fd(f) under constraints at low frequencies and in the near field. The invention also provides an echo reduction apparatus (6).