Abstract: A method and system for generating parametric output directly from a prerecorded and error corrected parametric signal for playback in a parametric loudspeaker system. The method includes the step of retrieving a pre-encoded audio signal from an electronically readable storage medium. In addition, an ultrasonic carrier signal has at least one sideband which represents the pre-encoded audio signal. The next step is playing back the pre-encoded audio signal through an ultrasonic amplifier and emitter.

Abstract: A power amplifier for a parametric loudspeaker system which utilizes switch-mode power conversion to increase efficiency. The power amplifier is configured to coordinate the switching frequency of the amplifier with the carrier frequency of the parametric loudspeaker system, so a lower switching frequency may be used even though the power amplifier must amplify ultrasonic signals. The amplifier can be further optimized to counteract the reactance of the transducer load at the carrier frequency.

Abstract: A signal processing system for use in a multichannel audio system. The signal processing system includes a first channel having a first audio signal. A second channel is included that has at least a second audio signal. A processor is included that is responsive to a signal level threshold in the first channel, such that at the threshold and above the threshold, a portion of the first channel audio signal is mixed into the at least a second audio channel.

Abstract: A system for generating at least one remote virtual speaker location in connection with at least a partial reflective environment (12, 12, 14 or 15) in combination with an audio speaker for creating multiple sound effects including a virtual sound source from the reflective environment which is perceived by a listener (53) as an original sound source, by generating a primary direct audio output by emitting audio compression waves toward a listener, and generating a secondary indirect audio output from at least one virtual speaker (24, 25 or 26) remote from the audio speakers, by emitting ultrasonic sound from at least one parametric speaker (20, 21 or 22) associated with the audio speakers and oriented toward at least one reflective environment which is remote from the audio speakers.

Abstract: A system configured to dynamically adjust the ultrasonic carrier level in a parametric array system in response to changing source signal input levels, and which employs a look-ahead delay strategy to enable optimal modulation of the carrier wave to eliminate constant ultrasonic carrier emission and reduce the ultrasonic carrier emission to what is actually needed to accommodate the db range of the source material, and at the same time, to also minimize noticeable distortion and sound artifacts of a high-power ultrasonic carrier, and/or distortion/artifacts arising from modulation of an ultrasonic carrier to reduce average power output; and thus it realizes advantages of carrier modulation based on source-signal level, while minimizing inherent drawbacks of carrier modulation.

Abstract: A parametric loudspeaker system using improved modulators to compensate for the non-linearity of the parametric process in air when driving the air at saturation levels and below saturation levels. The parametric loudspeaker uses a pre-processed single sideband modulator that offers ideal linearity as characterized by square root pre-processed double sideband modulators but with a lower carrier frequency and without the wide bandwidth requirements. By eliminating some or all of the lower sideband the carrier frequency can be reduced without producing sideband frequencies in the audible range. Lower operational frequencies result in greater translation efficiency and greater output capability before reaching the saturation limit of air. A pre-processor minimizes the effects of saturation limits for double sideband, truncated double sideband or single sideband processing to achieve superior output.

Abstract: An electrostatic loudspeaker requires a high voltage DC bias power supply to bias the stators and diaphragms of electrostatic speakers. A self biased power supply eliminates the need for an external power supply by deriving a high voltage bias from the stator AC signal voltages which have been rectified and run from a high voltage tap and/or through a voltage multiplier which has a voltage limiting means.

Abstract: A planar-magnetic electro-acoustic transducer including a support structure and a magnetic structure carried by the support structure, the magnetic structure comprising a multiplicity of high-energy magnets configured so as to have shared loop field maxima and local loop field maxima, and a diaphragm carried by the support structure, comprising a plurality of conductors carried by and coupled to the diaphragm, said conductors being disposed in relation to local loop maxima and configured to exploit the energy of local loop maxima, as well as the energy of shared loop maxima in driving the diaphragm to produce an acoustic output; and the magnetic structure can be configured so that it includes magnet rows, and the transverse cross-sectional width of the magnets does not exceed their transverse cross-sectional height, and the distance between adjacent elongated magnet rows is greater than one half the width of either of the magnets of the adjacent magnet rows.

Abstract: A bandpass loudspeaker enclosure having three sub chambers, a first subchamber being a Helmholtz-reflex chamber with a passive acoustic radiator operating in parallel with the transducer, and the remaining two chambers utilizing two passive acoustic radiators to achieve three Helmholtz-reflex vent tunings and a multiple of low pass acoustic filters that provide an acoustic bandpass with reduced diaphragm displacement and substantially reduced distortion and pipe resonances above the pass band. A further embodiment provides a reduced lowest frequency vent size for a given low frequency subchamber size and tuning frequency.

Abstract: A sound emitting device for providing at least one new sonic or subsonic frequency as a by-product of emitting a waveform of at least two ultrasonic frequencies whose difference in value corresponds to the desired new sonic or subsonic frequency. The device includes a parametric emitting perimeter or plurality of emitter segments positioned around a central open section. This open section is structured with a diagonal width greater than a cross-sectional diagonal of the parametric emitting perimeter. An ultrasonic frequency signal source and sonic/subsonic frequency generator are coupled together to a modulating circuit for mixing an ultrasonic frequency signal with an electrical signal corresponding to the at least one new sonic or subsonic frequency. The modulator output is coupled to the emitting perimeter which comprises ultrasonic frequency emitting material for propagating the mixed waveform into air for demodulating the waveform to generate the at least one new sonic or subsonic frequency.

Abstract: A planar magnetic transducer having enhanced magnetic structures which increases performance over a single-ended device but mitigates some of the drawbacks of double ended devices, including a supporting structure, a diaphragm incorporating a coil conductor at least a primary magnetic structure, and a secondary magnetic structure can be added, including mitigation of high frequency resonance and attenuation by providing a more open architecture, including spacing the magnets wider apart, configuring the inter-magnet spaces to provide better acoustic performance, using high-energy magnets, which magnets can be shaped to form at least a part of the shaped inter-magnet space.

Abstract: A sonic emitter, horn array with enhanced emitter-to-air acoustic coupling, with particular application to ultrasonic frequencies. The emitter comprises a plate support member having opposing first and second faces separated by an intermediate plate body. The plate body includes a plurality of conduits configured as an array of acoustic horns, with a small throat opening at the first face and an intermediate horn section which diverges to a broad mouth opening at the second face. An emitter membrane is positioned in direct contact with the first face and extends across the small throat openings. The emitter membrane is biased for (i) applying tension to the membrane extending across the throat openings and (ii) displacing the membrane into a non-planar configuration.

Abstract: A parametric loudspeaker which uses multiple piezoelectric bimorph transducers. These multiple piezoelectric bimorphs have a resonant frequency which varies from unit to unit. The phase response at and near the resonant frequency changes at a very high rate with slight changes in frequency. The associated modulator electronics have a primary carrier frequency that is optimized for maximum parametric output. This is achieved by aligning the carrier frequency with the flattest portions of the phase curve for maximum phase coordination among the multiple devices.

Abstract: A system for generating at least one remote virtual speaker location in connection with at least a partial reflective environment (12, 12, 14 or 15) in combination with an audio speaker for creating multiple sound effects including a virtual sound source from the reflective environment which is perceived by a listener (53) as an original sound source, by generating a primary direct audio output by emitting audio compression waves toward a listener, and generating a secondary indirect audio output from at least one virtual speaker (24, 25 or 26) remote from the audio speakers, by emitting ultrasonic sound from at least one parametric speaker (20, 21 or 22) associated with the audio speakers and oriented toward at least one reflective environment which is remote from the audio speakers

Abstract: An electrostatic loudspeaker includes a high resistivity stator with electrode conductivity per square that is constant and/or decreases with distance from the connection point. A contact area of predetermined size is related to the highest frequency of interest. The constant or decreasing surface resistivity of the stators, interacting with the capacitive load of the stator to stator gap, operates as a distributed network such that the active acoustic output is attenuated in a predetermined manner with increased frequency at all points equidistant on the stator from the connection area. The apparent acoustic source size is reduced as the frequency increases to maintain enhanced dispersion across the operating range of the loudspeaker system.

Abstract: A bandpass loudspeaker enclosure system including at least one electro-acoustic transducer with a vibratable diaphragm having a first acoustical coupling surface and a second acoustical coupling surface, and at least one differential area passive radiator with three separate acoustical coupling surface areas. The first acoustical coupling surface of the vibratable diaphragm is substantially air coupled through a first enclosure volume to a first of the three separate acoustical coupling surface areas of the at least one differential area passive radiator. A second of the three separate acoustical coupling surface areas of the at least one differential area passive radiator is substantially air coupled through a second chamber to the external environment through a restricted acoustic opening or passive acoustic radiator of predetermined characteristics.

Abstract: A power transfer system for converting recurring wave movement within the ocean to electrical energy. The system comprises pressure sensing structure such as a pressure transducer 10 or combination movable magnet and coil 50, positioned below water level and at a location 20 of wave movement for (i) registering changes in height of water 18 and 19 above the pressure sensing structure 10, 50 and (ii) providing electrical power output at the ocean floor corresponding to changes in gravity force associated with the changes in the height of water. A transfer medium 12 is coupled at one end to the pressure sensing structure and extends at a second end to a shore location. A power receiving device such as a bank of storage batteries 14 or electrical load is coupled to the transfer medium at the shore location for receiving the power output from the transfer medium and for processing the power for use.

Abstract: A signal processing system for use in a multichannel audio system. The signal processing system includes a first channel having a first audio signal. A second channel is included that has at least a second audio signal. A processor is included that is responsive to a signal level threshold in the first channel, such that at the threshold and above the threshold, a portion of the first channel audio signal is mixed into the at least a second audio channel.

Abstract: An electrostatic loudspeaker requires a high voltage DC bias power supply to bias the stators and diaphragms of electrostatic speakers. A self biased power supply eliminates the need for an external power supply by deriving a high voltage bias from the stator AC signal voltages which have been rectified and run from a high voltage tap and/or through a voltage multiplier which has a voltage limiting means.

Abstract: A parametric loudspeaker system using improved modulators to compensate for the non-linearity of the parametric process in air when driving the air at saturation levels and below saturation levels. The parametric loudspeaker uses a pre-processed single sideband modulator that offers ideal linearity as characterized by square root pre-processed double sideband modulators but with a lower carrier frequency and without the wide bandwidth requirements. By eliminating some or all of the lower sideband the carrier frequency can be reduced without producing sideband frequencies in the audible range. Lower operational frequencies result in greater translation efficiency and greater output capability before reaching the saturation limit of air. A pre-processor minimizes the effects of saturation limits for double sideband, truncated double sideband or single sideband processing to achieve superior output.