DK50698C
(en )
1935-09-30
Electrodynamic sound reproducing apparatus.
FR761302A
(en )
1934-03-16
Photophonographic apparatus
DK46112C
(en )
1932-08-29
Device by Light emitters in Sound reproducing apparatus.
DK48115C
(en )
1933-12-04
Gymnastic apparatus.
DK46775C
(en )
1933-01-16
Device for sound reproducing apparatus.
ES124976A1
(en )
1932-02-16
Improvements in sound reproduction devices.
ES124566A1
(en )
1931-12-01
Improvements in sound recording devices.
FR753206A
(en )
1933-10-11
Photophonographic apparatus
ES123179A1
(en )
1931-07-01
Improvements in sound film projection apparatus.
DK47661C
(en )
1933-08-21
Sound reproducing apparatus.
DK44635C
(en )
1931-09-28
Sound reproducing apparatus.
FR724668A
(en )
1932-04-30
Amplifier phonograph
DK46816C
(en )
1933-01-23
Device for Miniature Pianos.
DK51614C
(en )
1936-05-11
Sound reproducing apparatus.
ES125964A1
(en )
1932-04-16
Improvement in sound recording devices.
CH152937A
(en )
1932-02-29
Device for showing optical sound films.
ES123361A1
(en )
1931-08-01
Improvements in the apparatus for the reproduction of sound with the help of light.
FR733607A
(en )
1932-10-08
Sound projector device
DK47033C
(en )
1933-03-06
Device by Speakers.
DK47487C
(en )
1933-06-26
Advertising apparatus.
ES122873A1
(en )
1931-06-16
Improvements introduced in the apparatus for cinematographic sound reproduction.
DK47866C
(en )
1933-10-09
Combined electric Light and Sound signal device.
ES129851A1
(en )
1933-04-16
Improvements in optical devices for recording sound.
FR720943A
(en )
1932-02-25
Sound synchronoscope
FR721707A
(en )
1932-03-07
Lighting device for playing sound films