5,253,301

43.38.Ja NONDIRECTIONAL ACOUSTIC GENERATOR AND SPEAKER SYSTEM

Industrial Research Products. The patent document argues that neither the linear phase nor minimum phase approach is well suited for use in hearing aids. An improved equalizer network is described that can be implemented with either analog or digital circuitry.--GLA

Masakatsu Sakamoto, Shiro Iwakura, and Kaoru Yamazaki, assignors to Kabushiki Kaisha Kenwood

12 October 1993 (Class 381/89); filed in Japan 31 March 1989

Loudspeakers 3 and 4 are mounted in respective enclosures 1 and 2 and sound is squirted out through slot 5 formed by the space between the two boxes. That's just for starters; more than a dozen variants are de- scribed. The novel feature that distinguishes these from numerous prior slot-loaded or radial horn designs is the use of two push-push loudspeak-

ers. "Acceleration speed of (the) air is two times as fast as a conventional speaker, to thereby improve the speaker efficiency two-fold." Actually, with the geometry shown, it's more like five times. Are we to infer that conversion efficiency is five times greater than if the two cabinets were simply set side by side?--GLA

5,228,092

43.38. Kb VOICE TRANSDUCER

Yasuji Nakamura and Hisanori Kanasashi, assignors to Matsushita Electric Industrial Company

13 July 1993 (Class 381/151); filed in Japan 26 June 1990

Contact microphones for mobile communications can be positioned at the top or back of the talker's head. The patent describes an improved, headrest-mounted design that maintains optimum physical contact while minimizing unwanted noise pickup.--GLA

5,233,661

43.38. Lc SOUND FIELD VARIABLE APPARATUS

Akihisa Kawamura et aL, assignors to Matsushita Electric Industrial Company

3 August 1993 (class 381/61); filed in Japan 19 April 1990

An electroacoustic system for a playhouse or recital hall includes separate processing of direct sound pickup and one or more individual indirect sound amplification systems. Adaptive filters arc used as echo cancellers in the indirect systems. "By varying the sound volume balance of direct sound and indirect sound speakers in accordance with the pur- pose or characteristics of a performance to be held, the sound field can be reproduced naturally and responsively."•GLA

5,233,665

43.38. Lc PHONETIC EQUALIZER SYSTEM

Gary L. Vaughn and James L. Harrison, assignors to Gary L. Vaughn, Albuquerque, NM

3 August 1993 (Class 381/97); filed 17 December 1991

Previously it has been demonstrated that a tapped, analog delay line can serve as the backbone for a practical audio equalizer. Tattersall de- scribed such a linear phase active filter in 1981, and a subsequent minimum-phase circuit designed by Peters is currently manufactured by

5,126,543

43.38. Md INTEGRATED HAND MICROPHONE WITH BARCODE READER AND DICTATION CONTROLS

Lawrence E. Bergeron et al., Trumbull, CT 30 June 1992 (class 235/462); filed 27 November 1989

A combined microphone bar code sensor includes within a housing a microphone, a/fUnction switch to control dictation functions, a bar code sensor for optically sensing bar code indicia and electrical signals, in response to the actions occurring at or on the components.--MDB

5,193,141

43.38. Md VEHICULAR VOICE STORAGE, PLAYBACK, AND BROADCASTING DEVICE

Arthur L. Zwern, San Jose, CA 9 March 1993 (class 395/2); filed 19 November 1990

The patented device is a dashboard-mounted controller for record- ing and reproducing a user's voice messages in an automobile. The adap- tivc delta modulation method of speech coding provides adequate quality of reproduction with a reasonable limit on the memory needed for mes- sage storage. Provision is made for output to an external loudspeaker or to the loudspeakers in the passenger compartment. A selector switch determines which of several stored phrases is played or which is to be erased and re-recorded.--DLR

5,237,559

43.38.Ne REPRODUCTION OF SOUND TRACK SIGNALS BY VARYING THE DETECTOR THRESHOLD LEVEL AS A FUNCTION OF THE TRANSVERSE SCAN POSITION

James B. Murphy and Martin J. Richards, assignors to Dolby Laboratories Licensing Corporation

17 August 1993 (Class 369/125); filed 5 September 1991

Like most Dolby Laboratories patents, this one is long, thorough, and interesting. Previous methods of reducing noise pickup from variable- area, optical sound tracks arc reviewed. An improved system is then described that is said to offer improved noise reduction capabilities while keeping distortion at a minimum. Anyone interested in motion picture sound will want to obtain a copy of the patent.--GLA

5,125,032

43.38.Si TALK/LISTEN HEADSET

Erwin Meister and Edwin Bollier, Zurich, Switzerland 23 June 1992 (Class 381/183); filed in Switzerland 2 December

1988

A talk/listen headset comprising ear protection capsules, two bone conduction pickup transducers, and an earphone is described. One pickup transducer is positioned on the zygomatic arch of the wearer, the other on the ascending ramus of the wearer's jaw. Additionally, an externally di- rected microphone may be added to sense background noise to limit the sound level of this noise experienced by the wearer, with the aid of control circuits.---MDB

2297 J. Acoust. Soc. Am., Vol. 95, No. 4, April 1994 Review of Acoustical Patents 2297

Redistribution subject to ASA license or copyright; see http://acousticalsociety.org/content/terms. Download to IP: 131.111.164.128 On: Sat, 20 Dec 2014 02:03:35