From: Patent Tactics, George Brock-Nannestad
On 9 Jun 2003 Bradleys wrote:
> Responding to Stephen Sutton's comment and Don Cox's post about advantages
> and disadvantages of listening to mono-music in stereo versus mono:
> Some may wonder how it could be possible in stereo to hear sound from other
> than being at a speaker or between speakers.
----- the whole concept of stereo enhancement and encoding is thoroughly
treated in publications by the Audio Engineering Society, Inc. It is
recommended to visit their website www.aes.org and to search for literature
of this kind.
> If someone used a stylus to play back a 78 rpm record (perhaps recording
> during playback) that was a stereo type stylus except that of course 78 rpm
> records were mono-recordings, I imagine that one stereo channel would pick
> up ..............................
I am interested in such matters [pops, cracks, their removal, vector addition
of signals, etc., GBN note] but I have not had recent experience
> with 78rpm records. I have been receiving posts to this list for only a
> short time and I think this is my first post. Is such a method known and
> used by those recovering recordings from 78rpm records? If it is a well
> known technique, I apologize for bringing it up. If it is not known has it
> been tried?
----- I would suggest to the Bradleys that it would be a good idea to read up
on mechanical recording and reproduction, in particular mono and stereo
disc records. Not the least Alan D. Blumlein's fundamental patent will give a
lot of food for thought. That historical text as well as a large part of what
has been written on the subject since 1950, with varying degrees of
mathematics, will be found in other publications from the AES, in particular
their two large anthologies on Disc Recording and Reproduction. They are
highly recommended, but to some seem strangely irrelevant in our digital
days. We must not forget, however, that for anything digital to be made to
the signals from mechanical records, we have to extract these signals with
as much information as possible.