PH

2T. 2W.

-- LH --J

mereus diagrams and performance graphs are included.--GLA

5,287,412

43.38.Ja ARRANGEMENT FOR REPRODUCING BASS TONES IN A VEHICLE

Hubert Etzel et al., assigners to Nokia (Deutschland) GmbH 15 February 1994 (Class 381/86); filed in Germany 28 June 1991

A small bandpass loudspeaker system is concealed in the center arm- rest of an automobile. The exit port is located such that it is unobstructed whether the armrest is up or down.mGLA

5,287,413

43.38.Ja DUAL VOICE COIL SOUND REPRODUCING DEVICE

William J. Ashworth, Altamonte Springs, FL 15 February 1994 (Class 381/194); filed 24 April 1992

The inventor has taken one of his screw-in inertia transducers and

equipped it with dual voice coils, to be driven from a two-channel stereo- phonic signal. Electronic coupling between the coils is said to be beneficial because lower audiofrequencies are effectively boosted.--GLA

5,295,194

43.38.Ja MULTI-DRIVER LOUDSPEAKER

ASSEMBLY

Eugene J. Christensen, Queensbury, NY 15 March 1994 (Class 381/192); filed 29 May 1991

A self-contained piezoelectric tweeter is rigidly affixed to the voice- coil former of a moving-coil woofer. The relative virtues of this arrangement are extolled through seven long pages of patent text.--GLA

5,280,543

43.38.Lc ACOUSTIC APPARATUS AND DRIVING

APPARATUS CONSTITUTING THE SAME

Kenji Yokoyama and Masao Nero, assigners to Yamaha Corporation

18 January 1994 (Class 381/96); filed in Japan 26 December 1989

This patent may win the 1994 award for tautological titles. The patent itself is based on an interesting concept: A self-powered loudspeaker driven by a conventional power amplifier. Additional current is supplied as needed to realize a desired transfer function, which may involve motional feedback or negative impedance. The patent is interesting and clearly written.--GLA

5,298,692

43.38.Si EARPIECE FOR INSERTION IN AN EAR

CANAL, AND AN EARPHONE, MICROPHONE, AND EARPHONE/-MICROPHONE COMBINATION COMPRISING THE SAME

Yasuo Ikeda and Yoshiuki Magara, assigners to Kabushiki Kaisha Pilot

29 March 1994 (Class 181/135); filed in Japan 9 November 1990

An earpiece having two main portions is described. A removable canal portion of appropriate size can be selected and snapped onto a body part. A single earphone or both a microphone and an earphone may be mounted to the body part. The device is stated to fit comfortably in most ears.--SFL

5,261,005

43.38.Vk SOUND FIELD CONTROL DEVICE

Iwamatsu Masayuki, assigner to Yamaha Corporation 9 November 1993 (Class 381/18); filed in Japan 9 October 1990

The patent attempts to provide more spacious, nonlocalized surround sound from Dolby encoded stereophonic source material. Multiple delays representing large-room reflections are added separately to signals driving front-left, front-right, rear-left, and rear-right loudspeakers.--GLA

5,253,222

43.38.Zp ONMIDIRECTIONAL FIBER OPTIC HYDROPHONE

B. A. Danver and D. Meyer, assignors to Litton Systems, Incorporated

12 October 1993 (Class 367/149); filed 9 April 1993

An omnidirectional fiber optic hydrophone comprises two upstanding ring assemblies 22 and 24, each of which is actually a pair of concentric rings separated by air gaps 32 and 38, and which support opposite end plates 18 and 20. End plate 18 might be mounted directly to a ship's hull. Two different optical fibers (not shown) are wound and attached, one on the outermost cylindrical surface of ring assembly 24 and the other, on the innermost cylindrical surface facing the air gap of assembly 22 (other ar- rangements are discussed.) The whole assembly, with the exception of the numerous internal air voids which communicate to the surrounding medium

1944 J. Acoust. Soc. Am., Vol. 96, No. 3, September 1994 Reviews of Acoustical Patents 1944

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