Abstract: A speaker system and method, in which the intelligibility of reproduced speech or music sound, derived from an audio program signal, is enhanced by means of at least one of a first and second transfer function of a signal process applied to the audio program signal. The first transfer function incrementally varies the volume of the reproduced sound directly as a function of the volume of ambient noise. The second transfer function incrementally or continuously varies the high frequency response of the reproduced sound inversely as a function of the volume of the ambient noise. The ambient noise can be measured by a microphone, for example, located on or near the speaker system and can also be electronically averaged over a predetermined time period. The signal process provides an audio output signal that is applied to at least one amplifier and at least one speaker.

Abstract: Systems and methods are disclosed for the derivation of improved DTM dynamic tinnitus mitigation sound formats. The system combines at least one recorded natural sound known to partially mask tinnitus with computer-generated sound that emulates such at least one natural sound and, in certain embodiments, further applies to at least one of the natural sound, computer-generated sound or combined sound at least one function of high frequency dynamic amplitude expansion, digital frequency shifting of high components to higher frequency ranges, selectable ones of a family of high frequency equalization curves, or band pass filtering. The resulting improved DTM sound exhibits a highly dynamic amplitude envelope and enhanced high frequency energy density, thereby providing superior tinnitus masking efficacy relative to prior art DTM and conventional masking sounds.

Abstract: A digital signal processing technique is provided for symmetrical stereophonic image enhancement in an automotive listening environment. The process introduces a rapid rate-of-change of phase shift between the channels, to a maximum of substantially 180 degrees, at substantially 200 Hertz. As an additional feature, spatial enhancement of the reproduced sound may be provided through the application of modified stereo difference signals prior to the image enhancement process.

Abstract: A frequency response compensation system for use with a planar diaphragm speaker mounted in an architectural wall, ceiling or sealed enclosure having a depth dimension limited by the interior depth of the ceiling, wall or enclosure. The compensation system combines signals derived from a modified high-pass filter stage, an unmodified signal path, and a gyrator stage so as to phase-interact with one another and provide a complex transfer function. An underdamped high-pass filter stage further enhances low bass performance. The frequency compensation system includes a main circuit board and a series of daughter boards that are adapted to be releasably connected to the main board. Each of the daughter boards contains a set of passive components having different component values that determine the specific response parameters of the various stages and circuits of the compensation system and is optimized for a specific planar speaker and enclosure combination.

Abstract: A stereophonic image enhancement signal processing system for vehicular sound systems provides a symmetrical improvement in imaging for listeners located at the left and right regions of a vehicle passenger compartment The stereo signals are processed in a manner to provide a rapid rate-of-change of phase equal to at least 90 degrees per octave approaching a maximum of 180 degrees between the stereo channels at approximately 300 Hz. A further enhancement of the reproduced sound stage is provided through the application of equalized stereo difference signals prior to, and in combination with, the above described phase shift process. An optional center channel signal, summed from stereo source signals, may be provided for driving a central speaker.

Abstract: A stereophonic signal processing system provides optimal spatial enhancement in a compact stereo sound system having limited physical separation between two relatively small stereo loudspeakers with accordingly limited low-frequency output capability. A difference signal is derived from the left and right stereo signals by subtraction in a a differential amplifier circuit, which may be made frequency-dependent so that the rejection of correlated information decreases with increasing frequency. The difference signal is processed through a frequency equalizer circuit, and an inverted version is derived via an inverter; the non-inverted and inverted difference signals are filtered according to a high-pass filter function having an upper-bass cutoff frequency selected to avoid excessive spatialization at low frequencies.

Abstract: A stereophonic signal processing system for enhancing the perception of sonic dimension and imaging in a sound reproduction system having at least two stereo speakers.

Abstract: Stereo processing circuitry is provided for modifying stereo signals so as to enhance the perception of imaging and ambience in non-ideal listening locations and confined environments such as the driver's location in a stereo-equipped vehicle. In a first modified mode, the stereo channels are symmetrically cross-coupled in additive polarity at high frequencies to enhance image localization, and in subtractive polarity over a full audio frequency spectrum to enhance stereo ambience. In a second modified mode, additional cascaded circuitry introduces frequency-selective polarity inversion and asymmetrical cross-coupling to compensate for the closer proximity of one of the loudspeakers to the listener's location, for the direct sound path from the nearer loudspeaker, and for the typical off-axis orientation of the nearer loudspeaker relative to the listener's position.

Abstract: The present invention is an improved two-channel, four loudspeaker-component enhanced stereophonic system which includes a pair of front loudspeaker systems, a pair of rear loudspeaker systems and a pair of speaker enclosures into each of which one of the front loudspeaker systems and one of the rear loudspeaker systems are placed. The enhanced stereophonic system also includes two electronic matrix networks which interconnect the input terminals of each front loudspeaker system to the left and right channel amplifier output terminals, respectively, and which also interconnect the positive input terminal of each rear loudspeaker system to the left and right channel positive amplifier output terminals, respectively. The electronic matrix networks include a first high-pass filter and a second high-pass filter each of which has an input terminal and an output terminal. The input terminal of the first high-pass filter is interconnected to the left channel positive amplifier output terminal.