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FR689442A - Improvements to electric megaphones - Google Patents

Improvements to electric megaphones

Info

Publication number
FR689442A
FR689442A FR689442DA FR689442A FR 689442 A FR689442 A FR 689442A FR 689442D A FR689442D A FR 689442DA FR 689442 A FR689442 A FR 689442A
Authority
FR
France
Prior art keywords
megaphones
electric
electric megaphones
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
Other languages
French (fr)
Inventor
Sidney George Brown
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed filed Critical
Application granted granted Critical
Publication of FR689442A publication Critical patent/FR689442A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/08—Mouthpieces; Microphones; Attachments therefor
    • H04R1/083—Special constructions of mouthpieces

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
FR689442D 1929-05-11 1930-02-05 Improvements to electric megaphones Expired FR689442A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB689442X 1929-05-11

Publications (1)

Publication Number Publication Date
FR689442A true FR689442A (en) 1930-09-05

Family

ID=10493053

Family Applications (1)

Application Number Title Priority Date Filing Date
FR689442D Expired FR689442A (en) 1929-05-11 1930-02-05 Improvements to electric megaphones

Country Status (1)

Country Link
FR (1) FR689442A (en)

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