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This technique has been used for decades by our government to extract information from noise. One example is submerged submarine communications where the noise level can exceed the signal level. I believe that one method is called autocorrelation. I do not have references, but perhaps some of the older methods have been placed in the public domain. Jerry hartke > -----Original Message----- > From: Association for Recorded Sound Discussion List > [mailto:[log in to unmask]] On Behalf Of Randy Riddle > Sent: Thursday, June 21, 2012 10:00 AM > To: [log in to unmask] > Subject: Re: [ARSCLIST] audio from pictures > > I've thought for some time that there's already a way to do this with > at least some recordings. > > For years, film restorers have used multiple prints of films, taking > the best quality sections from each that survive, sometime > substituting small sections in a print that has been damaged. > > Why couldn't that be done with recordings where multiple copies survive? > > Basically, what the software would do is let you take multiple sound > files sourced from different copies of the same record. Each will > have been damaged and degraded in different ways and have different > patterns of noise. > > The software, after synching the recordings, would compare them and > "toss out" the noise and keeping commonalities between the copies. > The more copies of the recording you have available, the better the > result might be, at least theoretically. > > Why couldn't this work? > > rand > > On Thu, Jun 21, 2012 at 9:24 AM, Tom Fine <[log in to unmask]> > wrote: > > Hi Steve: > > > > I agree with you in general, but I'm talking about recordings where > analog > > playback has produced poor results -- for instance the badly worn and > > super-rare Paramount blues records. No transfer I've heard using analog > > playback and whatever digi-trix the producer decided to use has produced > > very good-sounding results. > > > > I think the pot of gold at the end of the research rainbow for non- > physical > > playback of grooved media is the ability to "erase" all the noise that > comes > > from the media itself, and of damage to the media. Then, in theory (and > > sometime in the future) you'd just be reproducing the information > originally > > cut into the groove. > > > > For now, I wouldn't worry about your transfer business (or mine) being > under > > dire threat. But I hope I live long enough to see the day when putting a > > needle to an old groove for critical playback or transfer is considered > > obsolete. > > > > -- Tom Fine > >