Meyer Sound Laboratories, Incorporated

Paul J Kohut

John D Meyer

Jon M Arneson

Pablo Espinosa

Perrin Meyer

Roger Schwenke

Richard D Herr

Peter C Soper

Katrin M Rawks

Peter L Winship

Kurt Keown

Carlo Zuccatti

Alejandro Antonio Garcia Rubio

Peter Kowalcyzk

Justin Baird

Steven Metz

Pei-Yuan Liu

An apparatus for modifying a responsive liquid held in a barrel or other liquid container includes a transducer for producing vibration energy within the audio frequency range in response to an audio signal input and a coupler affixed to the transducer such that vibration energy produced in the transducer is transferred to the coupling device. The coupling device has a pusher end that extends beyond the front plane of the transducer and that contacts and pushes against the barrel wall when the apparatus is tied to the barrel wall. By determining the resonances of the liquid-filled barrel, audio input signals having sufficiently high levels at determined resonant frequencies can be chosen to achieve a maximum response in the liquid contained in the barrel. The apparatus is particularly suited for the sonic aging of whisky.

Apparatus and method for modifying a responsive liquid held in a liquid container having resonant frequencies in the audio frequency range

An improved filtering system for loudspeaker equalization is comprised of two filtering sections, a single pole filtering section having single pole filters for shaping the frequency response of the audio signal over the operative bandwidth of the equalized loudspeaker system, and a parametric filtering section that provides for localized parametric equalization for compensating for room or other environmental resonances. The filtering system of the invention can be used to create a wide variety of useful filter shapes, while minimizing phase distortion that can harm the transient response of phase-aligned loudspeakers of a loudspeaker system.

Filtering system for equalizing a loudspeaker system

A circuit for reducing noise in Class D amplifiers has a power stage voltage control means () responsive to defined signal conditions of the audio signal input (). The power stage voltage control means is operative to lower the voltage at the supply voltage input () of the amplifier's switching power output stage () upon the detection of a defined condition in the audio signal input such that the Class-D amplifier operates at reduced voltage ('idles') during the defined audio input signal condition.

Circuit and method for reducing noise in class D amplifiers

A loudspeaker system has a high frequency channel for driving a horn loaded high frequency transducer, and a low frequency channel for driving a low frequency transducer. A signal processing circuit is provided which has at least one first order and at least one second order cross-over circuit portion in the high channel and at least one first order and at least one second order cross-over circuit portion in the low frequency channel. These cross-over portions produce a cross-over frequency range for the loudspeaker system that is below the cut-off frequency of the horn. The signal processing circuit, including its cross-over circuit portions and in conjunction with the design of the expansion walls of the horn, extends vertical beamwidth control of the acoustic output of the loudspeaker system at the loudspeaker system's lower frequency range.

Loudspeaker system with extended constant vertical beamwidth control

A loudspeaker system has a plurality of relatively small transducer elements configured in a closely spaced transducer array such that their acoustic outputs combine to produce a focused beam of sound in front of the array that is substantially uniform about the beams radiation axis. The transducer array lies in a plane and has a perimeter that approximates a circle, and will have fill-factor with respect to a circle circumscribing the array of at least approximately 70%. In one variation of the loudspeaker system, the transducer array is constructed in smaller transducer array modules that are operatively fitted together to produce a larger array.

Loudspeaker system and method for producing synthesized directional sound beam

A circuit and method provides for the protection of transducers from over excursion, particularly for the protection of transducers for audio loudspeakers. A frequency dependent excursion limiter circuit has an initial summing stage followed by a shaping filter stage. A clamping function is provided at the summing stage, or at a separate stage between the summing stage and the shaping filter stage, for clamping the driving signal at a predetermined maximum voltage if the driving signal exceeds the predetermined maximum voltage level. The shaping filter stage provides a frequency response shaping function based on a predetermined frequency response shaping criteria which is related to the frequency dependent excursion limits of the transducers being protected from mechanical overload. An inverse shaping filter function is provided at the initial summing stage by providing feedback from the shaping filter stage, thus eliminating the need for a separate inverse shaping filter circuit before clamping. The inverse shaping filter function allows low level signals below clamping to pass through the circuit unaffected. A frequency dependent excursion limiter circuit is also provided in the closed loop circuit of servo feedback system for protecting transducers in a servo feedback system from over excursion.

Frequency dependent excursion limiter

An arrayable loudspeaker system having a horn-loaded high frequency compression driver and a low frequency cone driver radiates acoustic energy from a focal point in a polar radiation pattern having amplitude and phase and includes a signal conditioning circuit for amplitude equalization and phase correction. The horn of the system's horn-loaded compression driver is designed in cooperation with the signal conditioning circuit such that the focal point of the loudspeaker system is substantially frequency independent over the operating frequency range of the loudspeaker system and such that over this operating frequency range the loudspeaker's focal point remains substantially fixed in space. Any two or more of such loudspeaker systems can be arrayed by aligning them in respect to their frequency independent focal points and by rotating the loudspeakers about an axis passing through the aligned focal points to obtain a desired coverage. To facilitate alignment, suitable visual or mechanical indicators or locators can be placed on the tops and bottoms of the arrayable loudspeaker systems.

Arrayable two-way loudspeaker system and method

An acoustical transmitting system and method for producing a narrow beam of acoustic energy over a broadband operating frequency range utilizes a parabolic reflector dish, a horn-loaded compression driver for directing acoustic energy toward the dish's reflecting surface, and a low frequency driver mounted behind a central aperture in the dish for producing acoustic energy that combines and interacts with the reflected acoustic energy produced by the horn-loaded compression driver. An input signal processing circuit is provided to condition the audio signal to the horn-loaded compression driver and the low frequency driver to achieve on-axis gain and off-axis cancellations at low frequencies. The addition of the low frequency driver to the reflector dish system effectively extends the ability of the system to produce and transmit acoustic energy in a narrow distribution pattern at frequencies below 1000 Hz using a four foot diameter dish.

Broadband acoustical transmitting system

A method and correction circuit for improving and controlling the listening window and response of a two-way loudspeaker system utilizing a horn-loaded high frequency driver. The correction circuit includes adjustable active all-pass and band-pass filters, in a specific arrangement, coupled with conventional cross-over filters to achieve a maximally flat amplitude and phase response acoustically throughout a preferred listening window. A spectrum analyzer measures the near-field responses of the individual and combined transducers while adjustments are made. A phase shifting circuit is included in the low frequency channel which results in improved near-field to far-field response consistency and significantly improves the subjective characteristics of the high frequency horn.

Method and circuit for improving the polar response of a two-way

A circuit for improving the transient behavior of a two-way loudspeaker system includes a crossover circuit with high selectivity, amplitude and phase correction circuitry for separately correcting the amplitude and phase responses of the high and low frequency drivers in their mounting environment, and correction circuitry for correcting the composite amplitude and phase response of the overall loudspeaker system after insertion of the crossover. A further phase offset technique and circuit provides for introducing frequency dependent phase shift in the loudspeaker system's high or low frequency channels for offsetting the phase responses of the high and low frequency drivers within the crossover frequency range. According to the phase offset technique of the invention, phase shift is added, preferably in the high frequency channel, until composite amplitude response curves observed on-axis and at different vertical angles off-axis are forced to be consistent. After consistency is achieved the deterioration of the amplitude response resulting from the phase offset is corrected to a flat response by means of a forced series amplitude correction circuit inserted before the crossover. The result is improved transient response off-axis as well as on-axis.

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Pacheco, CA, United States of America

Paul J Kohut