Title:
Duplex loud-speaker
United States Patent 2638510
US Patent References:
Acoustic amplifier
- - 1759614

Sound reproducing device
- - 1907723

Acoustic apparatus
- - 2007747

Acoustic device
- - 2077170

Speaker unit
- - 2167625


Inventors:
Joseph, Brami
Publication Date:
05/12/1953
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Assignee:
Caesar, David Zeitouni
Primary Class:
381/341
Other Classes:
181/159, 181/144, 181/183, 381/160
International Classes:
H04R1/30; H04R1/22
US Patent References:
2214591Signal translating apparatus
2295483Loudspeaker
2301459Electric megaphone
2426948Coaxial dual-unit electrodynamic loud-speaker
Foreign References:
GB442900A