Title:
Directional acoustic system
United States Patent 2580439
Inventors:
Kock, Winston E.
Publication Date:
01/01/1952
Export Citation:
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Assignee:
BELL TELEPHONE LABOR INC
Primary Class:
379/420.02
Other Classes:
181/144, 367/176, 379/420.03, 379/432, D14/243
International Classes:
H04R1/34; H04R1/32
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US Patent References:
2483231Loud-speaking telephone set with low acoustic coupling
2423459Frequency selective apparatus
2411004Sound amplifying apparatus
2224698Telephone system
2177769Loud-speaking intercommunicating system
2033337Bifocal distance sound concentrator