I believe that you may be referring to the Theremin. It was a
musical instrument invented by a former Russian, Leon Theremin. It
utilized two antennae that were influenced by the operator's hands
relative to the antennae without touching. The electrico-magnetic
flux around the antennae were indiced by the relative distance on
one's hands to the emf. The electrical signals were affected, and
subsequently altered the pitch of the sound emitted from the
speaker. It was used for many sci-fi oriented films of it's day for
it's eerie sounding electronic sounds. Movies like "The Day the
Earth Stood Still" featured it in soundtracks and sound effects. It
has been rediscovered by later generations of music makers like,
Matthew Sweet.
Why would it be a Theremin? The Theremin does not sound like
this.
I appreciate your intent, but Theremin makes a simple gliding
pitch sound. Simple circuit. This sound is complex, many
pitches!
No, its got to be some combination of a few elements. You can
hear tape speed changes between the alternations (wow and flutter).
There is also a higher pitched sound riding on top of all of it
that seems to track with the tape pitch change. Too early for Moog
or Buchla, Arp etc (1963). Not a Novachord either. Sounds just like
a steady sound that the pitch changes via tape playback (or record)
speed change.
