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Class Information
Number: 381/75
Name: Electrical audio signal processing systems and devices > Megaphones
Description: Subject matter for amplifying the human voice and which is capable of being carried.

Patents under this class:

Patent Number Title Of Patent Date Issued
8611190 Bio-acoustic wave energy transducer Dec. 17, 2013
8354729 Gas sensor and manufacturing method thereof Jan. 15, 2013
8155339 Air-droppable loudspeaker Apr. 10, 2012
7912234 Acoustic projector for propagating a low dispersion sound field Mar. 22, 2011
RE42093 Active audio compressing in telecommunication Feb. 1, 2011
7686129 Acoustic horn having internally raised geometric shapes Mar. 30, 2010
7394905 Voice amplifier for mask Jul. 1, 2008
7231037 Active audio compressing in telecommunication Jun. 12, 2007
7088830 Parametric ring emitter Aug. 8, 2006
6947566 Method and apparatus for a portable public address system Sep. 20, 2005
6940984 Hands-free megaphone Sep. 6, 2005
6359990 Parametric ring emitter Mar. 19, 2002
6015160 Combined safety helmet and PA system Jan. 18, 2000
5859915 Lighted enhanced bullhorn Jan. 12, 1999
5640459 Portable voice amplifier Jun. 17, 1997
5463693 Voice amplification adapter assembly for face mask Oct. 31, 1995
4508936 Local external communication system Apr. 2, 1985
4400591 Simulated space helmet Aug. 23, 1983
4311872 Portable voice communication system Jan. 19, 1982
4237341 Portable self-contained amplifier and loudspeaker apparatus Dec. 2, 1980
4166926 Portable lectern and voice amplifier Sep. 4, 1979
4090033 Miniature portable public address system May. 16, 1978
4076957 Portable sound device for public address Feb. 28, 1978
4052561 Lectern with detent-hinged shelf for portable sound system Oct. 4, 1977

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