DK50698C
(en )
1935-09-30
Electrodynamic sound reproducing apparatus.
DK47638C
(en )
1933-08-14
Device for sound recording and sound reproduction.
FR725264A
(en )
1932-05-10
Further training for reproducers for phonographic amplifiers
DK46775C
(en )
1933-01-16
Device for sound reproducing apparatus.
AT112399B
(en )
1929-02-25
Sound recording and reproducing apparatus.
DK52843C
(en )
1937-03-22
Capacity surface for electrostatic devices for sound recording and sound reproduction.
DK48346C
(en )
1934-02-05
For sound recording and similar purposes determined Oscillograph.
DK55046C
(en )
1938-08-01
Device for photoelectric sound recording or reproducing apparatus.
DK46426C
(en )
1932-11-07
Device for Receiving and Reproducing Sound.
CA308520A
(en )
1931-02-10
Sound reproducing and recording device
CA308585A
(en )
1931-02-10
Sound recording device
ES126802A1
(en )
1932-07-01
Procedure of recording and reproduction of sounds.
CA312920A
(en )
1931-07-07
Device for recording sound
DK33968C
(en )
1924-12-22
Apparatus for apparatus for recording and reproducing phonographic sound waves.
FR724668A
(en )
1932-04-30
Amplifier phonograph
AT134391B
(en )
1933-07-25
Sound recorder and player.
ES121100A1
(en )
1931-01-16
A procedure for recording and reproducing sounds.
CA309870A
(en )
1931-03-31
Sound recording and reproducing apparatus
CA315648A
(en )
1931-09-29
Photographic sound recording apparatus
DK46707C
(en )
1933-01-02
Device for systems for reproducing recorded sounds.
ES122423A1
(en )
1931-07-01
Amplifier device for phonographs.
DK33887C
(en )
1924-11-17
Device for sound boxes for sound-recording and sound-reproducing gramophones.
AU2754530A
(en )
1931-02-19
Improved means for recording and/or reproducing sound
CA277544A
(en )
1928-01-31
Sound reproducing device
CA324284A
(en )
1932-07-19
Sound recording and reproducing apparatus