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US2864897A
(en)
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Universal phonograph pickup head or the like
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US2852604A
(en)
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Sound reproduction apparatus
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BE406882A
(https=)
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US1827051A
(en)
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Recording and reproducing system and apparatus
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US1952809A
(en)
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Sound reproducing apparatus
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US1728278A
(en)
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Electromagnetic translating device
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US1531252A
(en)
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Electrical reproducer for phonograph records
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CH462251A
(fr)
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Dispositif détecteur à seuil des vibrations d'un haut-parleur
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FR2515468A1
(fr)
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Ecouteur dynamique
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US1580954A
(en)
|
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Electromagnetic sound reproducer
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BE358204A
(https=)
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US2333517A
(en)
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Light valve
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US1759967A
(en)
|
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Electric sound transmitter
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US1557529A
(en)
|
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Electrical reproducer for phonographs
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FR2643493A1
(fr)
|
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Dispositif pour enregistrer, sonoriser des pages videotex et les reproduire en audio-visuel
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Collins et al.
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In/Out: Speaker as Microphone, Microphone as Speaker, the Symmetry of It All |
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US2042237A
(en)
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Travel sound source
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US1771323A
(en)
|
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Attachment for electric amplifiers
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Clark
|
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2 The Magnetic Recording |
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Kellogg
|
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The three-electrode vacuum tube as applied to the talking motion picture |
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US1329928A
(en)
|
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Sound-magnifying phonograph
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EP0223652A1
(fr)
|
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Convertisseur pour lecteur de compact-disques
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Hurst
|
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High fidelity sound reproduction |
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Hoxie
|
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The pallophotophone |
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Hartmann
|
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Audio Systems |