4,712,093 43.88.Lc AUDIBLE AUDIO LEVEL INDICATOR

Kenneth R. Reichel and Steve Hebrock, assignors to Audio Tech- nica U.S., Incorporated

8 December 1987 (Class 340/540); filed 10 April 1986

One or more tone generators take the place of a VU meter, giving an audible warning when the signal level exceeds a preselected threshold. A person monitoring a program may be unwilling or unable to keep his eyes on a VU indicator at the same time.--GLA

4,739,514 43.88.Lc AUTOMATIC DYNAMIC EQUALIZING

William R. Short and Malcolm Chellquist, assignors to Bose Corpo- ration

19 April 1988 (Class 381/103); filed 22 December 1986

Bose is one of the few loudspeaker manufacturers to make use of dy- namic low-frequency equalization. An earlier patent (4,490,843) argued that the accepted use of Fletcher-Munson curves for loudness compensa- tion led to subjectively unsatisfactory results. Instead, dynamic boosting of frequencies below 150 Hz or so was subjectively preferable. This improved

•-ii SOURCE WITH

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DY NAM I C EQUALIZATION

BANDPASS FILTER

version is based on an observation that, "...whenever the midband gain drops by substantially 10 dB, the gain in a narrow band of the low-pass frequency range should drop by only 5 dB and this two-to-one ratio extends over a wide range of gains." The patent is clearly written and easy to fol- 1ow.--GLA

4,674,743 43.88.Md ATHLETIC TRAINING UNIT WITH MUSICAL RHYTHM REPRODUCING SPEAKER AND EXERClSER'S PULSE DETECTING MEANS

Matsuo Hirano, assignor to Sanden Corporation 23 June 1987 {Class 272/100); filed in Japan 11 September 1985

An exercise baton houses a radio receiver, rhythm generator, two pow- er amplifiers, two loudspeakers, and a special circuit to monitor the user's pulse rate. Should it prove too difficult to miniaturize all of these compo- nents, the system can be housed instead in a small belt pack. "Alternatively, it can be also embodied in a comparatively large box type which is used on a floor near the exerciser."--GLA

strength hardened aluminum alloy, provided with a thin intermediate layer of glass having a surface capable of being made extremely flat and smooth (surface roughness of 40 nm or less), the glass layer being cemented to the carrier body.--MC

4,888,657

43.88.Qg CONTOURED HEAD ASSEMBLY FOR USE IN A CASSETTE LOADED RECORDER

Christopher A. Lacey and George W. Brock, assignors to Eastman Kodak Company

19 December 1989 {Class 360/122); filed 28 December 1987

To insure that the magnetic tape will always pass across a rounded head surface at a predetermined wrap angle, outriggers are added to the head structure at the approach and departure sides. Variations in dimen- sional tolerances in different tape cassettes that change the tape path slight- ly are corrected by the outriggers.•MC

4,888,658

43.88.Qg MAGNETIC HEAD FOR MAGNETIC RECORDING AND REPRODUCING UNIT

Mitsuaki Ono, Masataka Ueda, and Osamu Miyazaki, assignors to Matsushita Electrical Industrial Company

19 December 1989 {Class 360/126); filed in Japan 30 April 1985

A high-resolution magnetic head is made of blocks 1, 2 of MnZn ferrite reinforced by sendust inserts 3, 4 that define the head gap 5. The junctions 8, 8' if straight would create quasigaps that could cause hills and valleys in the

response curve. Here, the junctions are corrugated, and the corrugation dimensions can be adjusted to cancel specified wavelengths such as of color carriers in video tape recording.--MC

4,890,378

43.88.Qg METHOD FOR MANUFACTURING A MAGNETIC HEAD CORE HAVING A MAGNETIC FILM

Takashi Suzuki et al., assignors to Canon Kabushiki Kaisha 2 January 1990 {Class 29/603); filed in Japan 19 August 1985

High-resolution heads for high-coercivity tapes are mass produced by a process described in great detail with 40 pages of drawings. The novelty of this process is that the gap and its defining magnetic poles are all built up by successive evaporations on the face of one-half polepiece. The second-half polepiece is added later for mechanical reinforcement and wear resistance, but is not a part of the critical gap-defining structure.--MC

4,816,311

43.88.Qg RECORDING MEDIUM THAT CAN BE MAGNETIZED VERTICALLY AND METHOD FOR MANUFACTURING SAME

Armin Lenhart, assignor to Siemens Aktiengesellschaft 28 March 1989 {Class 428/64); filed in Germany 29 March 1985

A hard disc for ultra-high-density magnetic recording is coated with vertically oriented cobalt--chromium alloy. The carrier body is a high-

4,891,114

43.88.Qg MAGNETIC RECORDING MEDIA

Michael Hitzfeld, Werner Grau, and Joachim Hack, assignors to BASF Aktiengesellschaft

2 January 1990 {Class 204/192.15); filed in Germany 31 December 1986

Extremely high-magnetic recording densities have been obtained on recording media made of vertically oriented particles of cobalt-chromium alloy. This patent advocates a friction reducing overlayer of amorphous

2519 J. Acoust. Soc. Am. 88(5), Nov. 1990; 0001-4966/90/112519-02500.80; @ 1990 Acoust. Soc. Am.; Patent Reviews 2519

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