(((David Morton remarks: The Philips-Miller audio recording system was invented by an American, J.A. Miller, and licensed to the Philips company of Eindhoven. Philips marketed this system to radio broadcasters beginning in the mid 1930s, but apparently did not revive it after World War II. The system was in use at Radio Luxembourg and the BBC for several years, and the Norwegian broadcasting authority also installed a Philips-Miller recorder in 1936 and used it until it was replaced by tape recorders in 1950. In the U.S., station WQXR in New York briefly experimented with a Philips-Miller recording around 1938.)
R. Vermeulen "The Philips Miller System of Sound Recording" Philips Technical Review Vol 1 (April 1936): 107-114
"In the Philips-Miller method, as in the photographic sound-film processes, a sound-track is recorded on a strip of film. However, this is not done by optical means as hitherto, but by mechanical means. The film material, the 'Philimil' tape, consists of a celluloid base, which in place of the usual photographic emulsion is coated with an ordinary translucent layer of gelatine about 60 microns in thickness, on which a very thin opaque surface layer about 3 microns in thickness is affixed.
"Perpendicular to the tape, a cutter or stylus shaped like an obtuse wedge moves in synchronism with the sound vibrations to be recorded. This cutter removes a shaving from the gelatine layer which is displaced below it at a uniform speed. (...)
"Now if the cutter moves up and down in synchronism with the sound vibrations to be recorded (perpendicular to the tape), a transparent track on an opaque background will be produced on the moving tape whose width will vary in synchronism with the sound vibrations.(...)
"The recorded sound is reproduced by the usual method employed in optical sound-film technology. The film carrying the sound-track is moved between a photo-electric cell and a small, brightly illuminated slit (transversal to the direction of the motion of the film). The intensity of the light falling on the photo-electric cell thus varies with the variable width of the sound-track, and the resulting current fluctuations in the photo- electric cell are amplified and passed to a loudspeaker.
"The Philips-Miller system is thus a combination of a mechanical recording method with an optical method of reproduction. This unique association offers distinct advantages over the methods hitherto in use.(...)"
(((The article claims a frequency response of 25-8000 cycles for the apparatus, +-2 decibels.)))
David L. Morton (email@example.com)