Other

Carver, Inc.

James J Croft

Robert W Carver

Robert C Williamson

An audio frequency amplifier having a switching converter comprising source and sink rectifiers configured for sourcing and sinking current, in which the source and sink supply voltages of the rectifiers track the audio frequency signal being amplified. The amplifier has a circuit or element for discharging the output capacitors of the source and sink rectifier as necessary to prevent floating of the source and sink supply voltages. The discharging element can be a locking capacitor or one or more Zener diodes connected across the source and sink supply voltages. The discharge circuit can be one or more switching transistors connected across the freewheeling diodes of the source and sink rectifiers to actively pull the source and sink voltages down to discharge the output capacitors and thereby prevent floating. Low voltage rated parts can be used in the output stage amplifier, and in certain configurations a high voltage low current preamplifier stage can be eliminated.

Audio frequency power amplifiers

A dipole speaker for use with a multichannel sound reproduction system for producing an acoustical ambience signal. The dipole speaker comprises a transducer which is connected to the sound reproduction system so that it receives a difference signal from between the channels thereof. The transducer may be a unitary loudspeaker or a pair of identical, outward-facing loudspeakers. In response to a difference signal, the transducer generates first and second sound pressure lobes which extend in opposite directions from the dipole speaker, and which are 180 degrees out of phase so that they cancel one another out to produce a null zone which extends in a plane about the speaker. The dipole speaker is used in conjunction with conventional direct-path speakers which are connected to the sound reproduction system. The dipole speaker is positioned in a defined listening area so that the null zone is aligned towards the listener to avoid any sound travelling along a direct path from the speaker to the listener, and the sound pressure lobes are directed towards the walls of the listening area so that the acoustic signal of the dipole speaker is reflected therefrom and arrives at the listener by way of indirect paths. The acoustic signal of the dipole speaker is thus sensed by the listener as arriving from various directions, and its arrival is delayed relative to the arrival of the acoustic output of the direct-path speakers due to the longer lengths of the indirect paths, both of which enhance the ambience of effect of the acoustic output of the dipole speaker.

Dipole speaker for producing ambience sound

A loudspeaker diaphragm mounting system where there is a perimeter frame to which is mounted a planar flexible diaphragm having electrically conductive elements thereon. The frame has two perimeter sections which have matching perimeter grooves to receive an elongate tensioning member which presses the edge portion of the diaphragm into at least one of the grooves. By controlling the force with which the two frame sections are pushed together, tension on the diaphragm can be controlled.

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Seattle, WA, United States of America

James J Croft