5,384,851

43.38.Vk METHOD AND APPARATUS FOR

CONTROLLING SOUND LOCALIZATION

Junichi Fujimori, assignor to Yamaha Corporation 24 January 1995 (Class 381/17); filed in Japan 11 October 1990

A number of patents have been issued for circuits that electronically convert loudspeakers into virtual headphones and vice versa. In this in-

,21 22b 220 45

24 f •u l"-- _L•

- i 742 _jXi7,.•. 41 ' i 46

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stance, an interaural cross-talk canceling system is derived from a math- ematical matrix model. This is said to result in simpler processing circuitry (either digital or analog) and theoretically perfect cancellation.--GLA

5,404,406

43.38.Vk METHOD FOR CONTROLLING

LOCALIZATION OF SOUND IMAGE

Norihiko Fuchigami et aL, assignors to Victor Company of Japan 4 April 1995 (Class 381/17); filed in Japan 30 November 1992

Relatively simple digital filters are used to process a monophonic au- dio signal in such a way that, when reproduced through a pair of loudspeak- ers, apparent source location can be controlled as desired. The method is intended for use in "virtual reality" video games.--GLA

5,432,305

43.40.Ph PENETROMETER ACOUSTIC SOIL

SENSOR

George F. Nelson, assignor to Unisys Corporation 11 July 1995 (Class 181/101); filed 25 July 1994

Penetrometer probe 10 is connected to a long cylindrical housing 40 from which it is driven into the soil for determining the presence of mate- rials in the surrounding region. An electric pulse signal is applied through leads 15 to an electromagnetic striker 14 within mechanical impulse genera- tor 25 which also includes metal ring 13 intended for uniform and radial distribution of the impulse outward in a 360 ø circle into the surrounding soil. Sound-deadening material 16 is intended to isolate the input pulse from sound detector 24, although this seems unimportant since impulse generator 25 and detector 24 are coupled through the wall of cylindrical pipe 12, and the detector 24 is shut off at the moment of impact of striker 14. Acoustic detector 24 has a set of six circumferentially spaced geophones which re- spond differently, depending upon the angle, to the reflected impulse from

the exterior material. The angular location of the geophone having the maxi- mum response and the time delay between pulse sending and receiving give the penetrometer user the information needed to locate the material.--DWM

5,400,296

43.40.Tm ACOUSTIC ATTENUATION AND

VIBRATION DAMPING MATERIALS

William B. Cushman and Gerald B. Thomas, assignors to Poiesis Research, Incorporated

21 March 1995 (Class 367/1); filed 25 January 1994

Particles with high or low characteristic acoustic impedance, or mix- tures of such particles, are imbedded in a matrix of material that can support shear, with the intent of providing a composite that is light and relatively strong while acting as an effective acoustic barrier and vibration attenuator. The material is said to accomplish this in view of reflecting waves at im- pedance discontinuities, frictional energy dissipation at interfaces, and scat- tering energy from one wave type to others. Data on sound transmission through several ring-shaped samples are presented in the patent.mEEU

5,405,118

43.40.Tm RESILIENT SUPPORT ASSEMBLY PROVIDING VIBRATION SUPPRESSION

Peter Dietz et aL, assignors to Volkswagen AG 11 April 1995 (Class 248/632); filed in Germany 11 January 1992

This vibration isolator consists of a block of resilient material, such as rubber, that interconnects two metal elements. Inserts of a harder material are intended to scatter structure-borne sound waves traveling in the resilient matehal and to produce destructive interference in some frequency ranges.--EEU

5,410,906

43.40.Tm METHOD FOR DETERMINING DAMPING COEFFICIENTS

Stephen A. Austin et al., assignors to the United States of America 2 May 1995 (Class 73/11.04); filed 27 October 1993

The uniaxial damper of this patent is mounted between one end of a bar (e.g., of steel) and a rigid support; the other end of the bar is free. Values

3025 J. Acoust. Soc. Am., Vol. 98, No. 6, December 1995 Reviews of Acoustical Patents 3025

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