Abstract: A directional acoustic device configured for producing a directional output along an acoustic axis, including at least one transducer configured to create at least two wave trains which are directed along differing pathways by at least one wave guide, and so disposed that in directions more than ninety degrees off the acoustic axis the SPL of the output is greatly diminished by cancellation effects between the wave trains; improvement over previous gradient and quarter-wave pipe directional systems being enabled.

Abstract: Parametric sound reproduction in high-intensity audio signaling, for example in hailing and warning at relatively large distances, is disclosed in one example by producing a primary audio signal in the audio frequency range, and producing a secondary audio signal in the audio frequency range by modulation of the primary audio signal, wherein the primary signal is chosen to enable an improved effect, for example one of directional reproduction, exploiting greater sensitivity of human hearing, exploiting an efficient or maximum intensity frequency range of a transducer used to reproduce the audio signals, and another parameter effecting distance, intelligibility, or intensity of an audio signal.

Abstract: An acoustic human and animal behavior modification system that is capable of creating a zone of exclusion immediately adjacent a surface vehicle comprises an array of acoustic transducers disposed on the vehicle in a location not readily seen nor accessible by humans adjacent the vehicle, and is configured to project an acoustic output radially outward in a radial sector at sound pressure levels above the ordinary human pain threshold to motivate animals and humans to move away from a vehicle or change their behavior.

Abstract: A signal processing system for use in a multi-channel 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 directional acoustic device configured for producing a directional output along an acoustic axis, including at least one transducer configured to create at least two wave trains which are directed along differing pathways by at least one wave guide, and so disposed that in directions more than ninety degrees off the acoustic axis the SPL of the output is greatly diminished by cancellation effects between the wave trains; improvement over previous gradient and quarter-wave pipe directional systems being enabled.

Abstract: A speaker device for emitting subsonic, sonic or ultrasonic compression waves comprising a generally hollow drum, a rigid emitter plate attached to the drum, and a plurality of apertures formed within the plate which are covered by a thin piezoelectric film disposed across the emitter plate. A pressure source is coupled to the drum for developing a biasing pressure with respect to the thin film at the apertures to distend the film into an arcuate emitter configuration capable of constricting and extending in response to variations in the applied electrical input at the piezoelectric film to thereby create a compression wave in a surrounding environment. Parametric ultrasonic frequency input is supplied to the piezoelectric film to propagate multiple ultrasonic frequencies having a difference component corresponding to the desired subsonic, sonic or ultrasonic frequency range.

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 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 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 single end planar magnetic speaker system having at least one thin film, flexible diaphragm (72, 90) having a front side and a rear side for converting an input electrical signal into a corresponding acoustic output, the at least one diaphragm including a predetermined conductive region (76) and a predetermined non-conductive region; a magnetic structure (92) utilizing nonferite high energy magnets of a predetermined thickness wherein the magnets are each at least as wide as they are deep; the magnets having a magnetic strength wherein when compared to magnets of a ferrite type of same width as the nonferite high energy magnets but which have increased depth to yield at least nearly the same magnetic strength as the high energy magnets in the magnetic structure, doubling the depth of the high energy magnets in the magnetic structure, doubling the depth of the high energy magnets in the magnetic structure yields an increase in speaker sensitivity of at least 3 dB while the doubling the depth of the ferrite t

Abstract: A substantially single-ended planar-magnetic transducer comprises a thin film, diaphragm having a first surface side and a second surface side and including a conductive surface area for converting an input electrical signal into a corresponding acoustic output, said at least one diaphragm including a predetermined active region. A high energy magnetic structure has sufficient magnetic field strength and is configured with respect to the diaphragm to drive the diaphragm as a substantially single-ended audio transducer. Mounting structure is coupled to the diaphragm to hold the diaphragm in a predetermined state of tension and at a predetermined distance from the high energy magnetic structure over an extended period of time including periods of use and nonuse. The diaphragm provides improved performance characteristics by using a polyethylenenaphthalate film as a base material for the diaphragm.

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 method and device for frequency shifting and amplifying an audio signal for use in a parametric loudspeaker system is disclosed. The method includes the operation of receiving an input audio signal and creating a reference signal. The audio signal is compared with the reference signal to derive a compared product signal. The compared product signal is sent to a switching power stage. Nonlinear preprocessing is performed with respect to the input audio signal, and/or a non-triangle wave is created as the reference signal. The input audio signal is shifted and amplified by modulating the reference signal in the switching power stage.

Abstract: A method for the dissemination of audio information in a hostile environment via an airdrop to mainly illiterate populations in a target area by means of a leaflet (10, 14) containing audio circuitry (12). In the first step (1) the hostile target population is identified and the desired content of the audio information is selected. In the next steps, hardened, waterproof audio leaflets (10, 14) are manufactured (2) and recorded (4), (5) with the desired audio information. Finally, the audio leaflets are then airdropped (6) to the target population. The audio message is played (7) when the leaflet is activated by a member of the target population. The method is practiced using an audio leaflet designed to play an audio message. The leaflet (10, 14) is embodied in a protective structure capable of surviving (i) an impact resulting from and airdrop and (ii) extended exposure to adverse elements of nature for at least three days.

Abstract: A method and device for frequency shifting and amplifying an audio signal for use in a parametric loudspeaker system is disclosed. The method includes the operation of receiving an input audio signal and creating a reference signal. The audio signal is compared with the reference signal to derive a compared product signal. The compared product signal is sent to a switching power stage. Nonlinear preprocessing is performed with respect to the input audio signal, and/or a non-triangle wave is created as the reference signal. The input audio signal is shifted and amplified by modulating the reference signal in the switching power stage.

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: 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: 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 system for providing audio information to persons in an approach path (12) includes an interaction point (14), and an approach path (12) leading to the interaction point. A parametric sound system (18) is provided, which includes a parametric speaker (20) disposed adjacent to the interaction point. The parametric sound system is configured for limited delivery of sound in a spatially limited audio zone (24) along the approach path (12), within a decibel level above ambient noise levels in the area of the interaction point (14), and sufficiently high to be heard primarily by a person progressing along the approach path (12). The interaction point can be a cashier station, and the system can also include a video display (16) configured to provide video information to persons in the approach path along with the audio information.