Abstract: A coaxial speaker system having a high frequency component and a low frequency component is provided with a filtering circuit having an inductance coil securely mounted upon a magnet of the coaxial speaker. Mounting of this filtering circuit permits tuning of the coaxial speaker to provide a desired decibel level over a midrange frequency between the high frequency and low frequency components.

Abstract: A dipole loudspeaker includes a rigid support containing an opening and a generally planar multi-layered flexible diaphragm mounted on the support and extending across the opening. The diaphragm is formed of a plurality of layers of thin flexible membrane material, each of the layers having a different height and containing a thin electrical conductor arranged in a predetermined pattern on one surface thereof. The conductor patterns on each of the membranes have different masses, whereby the membrane defines along its height areas of various thickness and varying mass whereby the membrane is suitable for more accurately reproducing or generating high and low frequencies when the electrical conductors are connected with a source of sound signal currents. A plurality of magnets are mounted in spaced relation opposite at least one surface of the membrane and the conductor patterns for vibrating the membrane to reproduce the sound in response to the sound signal currents through the conductor.

Abstract: A cinema sound system for unperforated screens includes for each stereophonic channel a floor positioned direct radiator bass speaker unit radiating into quarter space and an upper frequency speaker unit mounted above the screen. Each upper frequency speaker unit includes a middle frequency driver mounted in a sealed rear enclosure which is attached to the throat of a middle frequency horn. A constant directivity high frequency horn with a high frequency driver attached to a rear end is mounted coaxially in the middle frequency horn. Sharp cutoff active crossover filters divide the input signal into low, middle, and high frequency band signals which are separately power amplified. The middle frequency horn is adapted to function as a direct radiator at a lower end of the middle band and as a sectoral horn above an unloading frequency of the middle frequency horn.

Abstract: A loudspeaker system which comprises a loudspeaker unit for radiating a first sound, a horn unit having a throat coupled to the back of the loudspeaker for radiating a second sound, and an acoustic filter provided in the horn for causing an acoustic impedance of the horn unit to be discontinuous. When the minimum frequency of cyclic dales of the sound pressure observed in the characteristic curves of a sound pressure of a composite of the first and second sounds as a result of a phase delay brought about by the length of the horn unit is expressed by fd, a primary harmonic resonance can be produced between the loudspeaker unit and the acoustic filter which is similar to that produced by a straight acoustic tube having its opposite ends closed, thereby to render the frequency of the primary resonance to be generally equal to the frequency fd.

Abstract: A multi-way loudspeaker system comprising at least two series connected loudspeakers (Z.sub.H, Z.sub.L) connected to a common signal input (1, 2) for reproducing different parts of the full frequency spectrum of an audio signal applied to the signal input and being provided with a passive dividing network including a first impedance (Z.sub.1) connected in parallel to a first loudspeaker (Z.sub.H) for reproducing a first part of the audio-frequency spectrum and a second impedance (Z.sub.2) connected in parallel to a second loudspeaker (Z.sub.L) for reproducing a second part of the audio-frequency spectrum. The loudspeaker system is provided with a compensating circuit consisting of a transformer (T) and an impedance (Z.sub.

Abstract: A loudspeaker device comprises an input circuit for obtaining an input signal to be sounded by a loudspeaker as a digital signal, a phase correction circuit for correcting the digital signal in phase, a loudspeaker drive circuit for producing a loudspeaker drive signal in accordance with the digital signal which has been phase-corrected by the phase correction circuit, and loudspeakers driven by the loudspeaker drive signal. The phase correction circuit consists of a digital filter capable of determining sound pressure-frequency characteristics and frequency-phase characteristics independently from each other. By determining the two characteristics in such a manner that, for example, the sound pressure-frequency characteristics will become flat and the phase-frequency characteristics will become linear, naturalness in hearing can be improved.

Abstract: A system for reproducing sound, particularly musical sound, giving enhanced pleasure to the listener. The system utilizes a pair of low frequency range speakers, a plurality of high frequency range speakers and may employ one or more mid frequency range speakers, all of which speakers are of conventional construction. These speakers are, however, disposed in a novel mechanical arrangement and electrically interconnected in a manner to emanate sound in essentially a non-directional manner. The listener thus perceives the sound to be emanating from the diemensional space surrounding the system, rather than from a single point or plane, and experiences the sound much as if he or she were in the same enclosure with live performers, rather than listening to a recording.

Abstract: The invention relates to a method for selectively restoring a sound signal delivered by an electric source in several parallel mounted transducers, each transducer being specialized for restoring a frequency range of the spectrum of the signal. The method consists more precisely in permanently fractionating the sound signal into frequencies so as to assign each component to the transducer optimized for the corresponding frequency range, without using any additional selection circuit such as filtering circuits.

Abstract: A loudspeaker system includes at least two loudspeaker drivers, together with an electrical crossover network having filter circuits with at least two separate mutually exclusive frequency passbands. The filter circuits comprising the crossover network each possess brick-wall amplitude responses, i.e., passbands with very high band-edge amplitude vs. frequency response slops, on the order of 100 dB/octave in the better embodiments. The high passband band-edge slopes, which are realized by the inclusion of transmission zeros in the separate crossover filter transfer functions, takes together with further appropriate crossover filter transfer function synthesis causes the separate loudspeaker drivers comprising the loudspeaker system to function independently of one another in their contribution to total system acoustic output.

Abstract: Disclosed is a passive delay network for insertion in the high frequency signal path of a crossover network in a high fidelity loudspeaker. The delay network provides means to adjust the optimum listening window electrically rather than by changes in the physical construction of the speaker cabinet. Electroacoustic high frequency and low frequency drivers may be mounted in a planar baffle or mounted co-axially. The delay network retains a "flat" amplitude-frequency characteristic and minimizes time dispersion in the acoustic signal received by the listener. Correction for time delay is most important near the transition frequency of the crossover network because near the transition frequency substantially equal sound energy is radiated by both the high frequency and low frequency drivers.Also disclosed is a novel construction for a co-axial driver combination and a technique for adjusting both the delay in the electric delay line network and the air path delay of electroacoustic drivers.

Abstract: A stereo loudspeaker system includes left and right loudspeaker cabinets each having a woofer mounted off center on the front baffle and tweeters mounted in front of the woofer with the axis of each tweeter at an angle to that of the woofer. Each cabinet includes a crossover network that intercouples the woofer and tweeter and controls the phasing of the tweeter with respect to the woofer to steer the radiation maximum of lower treble frequencies along an axis skewed from the fore-aft axis of the woofer. Left and right loudspeakers of the stereo system have symmetrical, mirror-image, crossfired, acoustic radiation patterns.

Abstract: A recreational cooler and speaker system includes an audio signal input terminal, such as an audio jack, on an outer wall of the cooler for driving speaker elements mounted to the cooler enclosure through an electrical path within the enclosure walls.

Abstract: A dihedral loudspeaker for use in mirror image stereophonic loudspeaker systems combines a pair of coaxial drivers with variable dispersion circuits and a high frequency delay network. The variable dispersion circuits decrease the amplitude of the electric signal to the indirect or ambient firing coaxial drivers relative to the direct firing drivers. Each coaxial driver combination comprises a high frequency driver in front of a low or mid-range frequency driver. The pair of coaxial driver combinations in each loudspeaker are substantially identical and each is effectively almost a point source of sound energy. The pair of coaxial drivers are located in dihedral baffles of the loudspeaker approximately the interaural distance apart. The variable dispersion circuits allow the loudspeakers to be adjusted such that listeners outside of the area between and in front of the loudspeakers hear an illusion of the sound image coming from the space between the loudspeakers.

Abstract: In a planar loudspeaker structure comprising planar membrane for forming a diaphragm on which a voice coil of a conductor pattern is formed, and a magnetic circuit for supplying a DC magnetic flux which crosses the voice coil, the conductor pattern includes first and second zigzag conductor pattern portions which are juxtaposed on substantially the entire area of the membrane and connected in series. Opposite ends of the series connection of the first and second conductor pattern portions are respectively connected to first and second terminals for receiving a low-band component of an input audio signal. A high-band component of the input signal is applied to a third terminal connected to a junction between the first and second conductor pattern portions and supplied only to the second conductor pattern portion.

Abstract: A device for converting an electric signal into an acoustic signal, which comprises an electro-acoustic transducer unit (2) having a quality factor (Q) less than unity. The device further comprises an amplifier circuit (3) for driving the transducer unit. The amplifier circuit has a frequency-dependent gain characteristic (6) which increases towards the lower frequencies, starting from f.sub.2, in a frequency range between a first and a second frequency (f.sub.1 and f.sub.2), f.sub.1 being the resonant frequency of the transducer unit (2) and f.sub.2 being greater than f.sub.1. The efficiency can be increased if amplifier the circuit includes a special amplifier such as a switched amplifier, for example, a class-D amplifier, or an amplifier with a power supply that provides a DC voltage that depends on the drive level of the amplifier.

Abstract: A multiple band automatic gain control circuit having a band splitter which is responsive to an input audio signal for separating the audio signal into plural components of different frequencies. Plural gain adjustment circuits each control the gain of an associated one of the components, wherein each of the gain adjustment circuits includes a voltage controlled amplifier, and feed forward control elements for controlling the voltage controlled amplifier as a function of the amplitude of the associated component. A signal combiner combines the gain adjusted components to thereby form a gain adjusted audio signal. A limiter circuit prevents the combined signal from exceeding predetermined amplitude constraints by simultaneously reducing the gain of all of the variable gain circuits whenever the combined signals exceed the predetermined constraints.

Abstract: A loudspeaker system for use with a stereo system having right R and left L signal outputs, has a right main speaker and right sub-speaker, and a left main speaker and left sub-speaker. Inter-speaker cabling means, which connect to the R and L signal outputs, apply an R signal to the right main speaker and an R-L signal to the right sub-speaker, as well as an L signal to the left main speaker and an L-R signal to the left sub-speaker. The inter-speaker cabling means includes impedances for substantially attenuating the -R portion of the L-R signal and the -L portion of the R-L signal for signal frequencies below approximately 200 Hz.

Abstract: A loudspeaker system includes a low-frequency driver and a high-frequency driver which are connected to a crossover network. The crossover network includes an inductor in series with the low-frequency driver for attenuating high-frequency signals at the crossover frequency and a capacitor in series with the high-frequency driver for attenuating low-frequency signals at the crossover frequency. An equalizer circuit connects between the high- and low-frequency drivers and operates to dampen resonant ringing which is otherwise produced. The equalizer circuit preferably comprises a series LRC circuit having a resonant frequency and a Q factor equal to the resonant frequency and Q factor of the circuit formed by the crossover network and drivers. The equalizer circuit is particularly suited for application in a disclosed loudspeaker system which utilizes a high inductance crossover inductor to enhance system bass response without sacrificing clarity.

Abstract: A speaker system includes crossover networks connected to a low output impedance amplifier through RF chokes. The individual outputs of the crossover networks are connected by separate wires to each of the individual speakers. RF reducing capacitors are connected across the terminals of each speaker and across the output terminals of the crossover networks. Separate back EMF resistors are connected across the speakers for dissipating back EMF signal energy. The component values in each of the crossover networks are split and balanced to present a substantially identical electrical configuration to both polarities of signal.

Abstract: A crossover network with a parallel resonant circuit in the high frequency branch is utilized to drive two loudspeakers, one in a low frequency range, and the other in the high frequency range. The resonant frequency of the resonant circuit lies in the upper end of the high frequency portion of the loudspeaker response.

Abstract: A dihedral loudspeaker for use in mirror image stereophonic loudspeaker systems combines a pair of coaxial drivers with variable dispersion circuits and a high frequency delay network. The variable dispersion circuits decrease the amplitude of the electric signal to the indirect or ambient firing coaxial drivers relative to the direct firing drivers. Each coaxial driver combination comprises a high frequency driver in front of a low or mid-range frequency driver. The pair of coaxial driver combinations in each loudspeaker are substantially identical and each is effectively almost a point source of sound energy. The pair of coaxial drivers are located in dihedral baffles of the loudspeaker approximately the interaural distance apart. The variable dispersion circuits allow the loudspeakers to be adjusted such that listeners outside of the area between and in front of the loudspeakers hear an illusion of the sound image coming from the space between the loudspeakers.

Abstract: Apparatus for reproducing sound having a realistic ambient field and acoustic image is used in a stereophonic sound reproduction system having a left channel output and a right channel output. A right main speaker and a left main speaker are disposed at right and left main speaker locations, respectively, which are equidistantly spaced from a listening location along a listening axis perpendicular to a line joining the left and right main speakers. A right sub-speaker and a left sub-speaker are respectively disposed at right and left sub-speaker locations equidistantly spaced from the listening location, and further from the listening location than the main speaker. In one particular arrangement each sub-speaker includes a driver and a tweeter, with the driver spaced a distance approximately 50% further from the main speaker location than the tweeter. The left and right channel outputs are respectively coupled to the left and right main speakers.

Abstract: A method and apparatus for improving the accuracy in locating psychoacoustic images in plural channels of related audio signals. Signals are cross-fed from one channel to another in an out-of-phase relationship with respect to the signals in the other channel. The phase relationship is such that it has not more than a single maximum with respect to frequency. Cross-feeding is limited to frequency components less than a predetermined value in the range of 1,000 to 5,000 Hertz. The overall gain of each of the audio channels in the frequency range of approximately 100 to 1,000 Hertz is greater when a signal is applied to that channel only, than when the signal is applied to both channels. When the same signal is applied to both channels, a dip in gain occurs for frequencies in the range of approximately 200 to 900 Hertz. Above the dip, the gain is relatively flat and below the dip, the gain increases gradually.

Abstract: A peak limiter is described which employs the Hilbert transform. Effectively distinct processing occurs for low frequency and high frequency signals and harmonic distortion results only when the limiter is excited by high frequencies.

Abstract: A loudspeaker system is provided wherein the coils, capacitors, and loudspeaker drive units and combinations thereof are resistively damped to provide electrical damping of the back EMF of these components and thereby reduce ringing in the loudspeaker crossover networks. The result is a measurable and clearly audible improvement in the accuracy of the sound produced by the loudspeaker system.

Abstract: An audio system, characterized in that the audio signal passes through a preamplifier, equalization unit and electronic cross-over and before reaching the power amplifiers, which drive the speakers, is modified by an electronic resonance control correction (ERCC) circuit.

Abstract: A signal processing system which can be readily adjusted to achieve a desired complex transfer function of arbitrary form. The system comprises a frequency sampling filter system from each individual filter of which in-phase and quadrature components are derivable. The sum of these components for all the filters is obtained to provide the output of the system, the proportions in which the components are summed being independently variable for each component, for example by adjustment of attenuators or multipliers. Such a system has particular application in the field of active sound control.

Abstract: A loudspeaker system with a plurality of direct loudspeakers mounted on an enclosure front for radiating in a forward direction and at least one compensation loudspeaker for each loudspeaker. The compensation speakers are mounted to direct sounds rearwardly so that both the sound pressure as a result of the direct sounds and the sound pressure as a sum of the direct and indirect sounds are substantially independent of frequency.