From Steven C. Barr: "...The intersting thing is that monophonic recordings
an audible amount of "room echo" ...have a certain stereo-like sense of
location, even though single-channel!..."
Frequency response is a major component of our depth perception. Most mono
recordings were recorded live to tape using one overall pickup mike with a
few "spot" mikes to add detail perhaps to the voice and rhythm section. The
overall mike captured the changes in frequency response caused by proximity
and the interference patterns caused by reflections from the room
The other component is the sense of spaciousness and envelopment caused by
changes in phase between low frequency sounds. It's ironic that single
subwoofer systems have become popular because this completely kills the
principal natural stereo effect that is the result of having multiple audio
channels. Of course it can also be argued that, with the exception of the
classical music genre, real stereo pretty much went away by the late 1960s.
Bob Olhsson Audio Mastery, Nashville TN
Mastering, Audio for Picture, Mix Evaluation and Quality Control
Over 40 years making people sound better than they ever imagined!