Abstract: A squeeze-stretch (also called, herein push-pull) loudspeaker or driver, such as an electret, can operate in an active noise reduction (ANR) earplug application. Other embodiments of a squeeze-stretch loudspeaker, such as piezoelectric bimorph and balanced armature, operate in a similar way, although they will differ in detail. Other applications, such as earphones for communication and entertainment, will benefit from the compact arrangement of components in a squeeze-stretch design. The advantages are a greater sound output from a smaller package, a smooth frequency response, and because of the diaphragm arrangement, less sensitivity to vibration.

Abstract: A transducer senses sounds produced by a talker or other source and measures acceleration of air. Enhancement of acceleration is accompanied by reduction of the portion of the sound energy that escapes from the regions around the transducer. The result is a high sensitivity transducer, with increased privacy for use in communication systems, especially cell phones and in a multi-person environment. A pressure sensor array with a weighted output is sensitive to sound from a source talker only, and not to acoustic background noise, and not to a local loudspeaker. The weighted signal is a source sum pressure signal. The array produces a signal (using a different weighting) that corresponds to an estimate of a derivative of pressure. The derivative signal is proportional to the volume velocity fluctuations produced by the source. This signal is enhanced, rather than reduced. A local loudspeaker is driven to make the source sum pressure signal as small as desired.

Abstract: A squeeze-stretch (also called, herein push-pull) loudspeaker or driver, such as an electret, can operate in an active noise reduction (ANR) earplug application. Other embodiments of a squeeze-stretch loudspeaker, such as piezoelectric bimorph and balanced armature, operate in a similar way, although they will differ in detail. Other applications, such as earphones for communication and entertainment, will benefit from the compact arrangement of components in a squeeze-stretch design. The advantages are a greater sound output from a smaller package, a smooth frequency response, and because of the diaphragm arrangement, less sensitivity to vibration.

Abstract: A transducer senses sounds produced by a talker or other source and measures acceleration of air. Enhancement of acceleration is accompanied by reduction of the portion of the sound energy that escapes from the regions around the transducer. The result is a high sensitivity transducer, with increased privacy for use in communication systems, especially cell phones and in a multi-person environment. A pressure sensor array with a weighted output is sensitive to sound from a source talker only, and not to acoustic background noise, and not to a local loudspeaker. The weighted signal is a source sum pressure signal. The array produces a signal (using a different weighting) that corresponds to an estimate of a derivative of pressure. The derivative signal is proportional to the volume velocity fluctuations produced by the source. This signal is enhanced, rather than reduced. A local loudspeaker is driven to make the source sum pressure signal as small as desired.