(10-21-2022, 09:16 PM)abaris Wrote: ... you can't filter out the damage ...
That's not what I was talking about. Transducing sound into an electrical signal and back into sound with early technology would do the equivalent, say, of making A sharp always sound like F flat, except, of course, the distortions would be many more than that. I'm suggesting that those properties are identifiable and measurable, and would permit "redistorting" the signal back to close to what it originally was as an acoustic signal. I haven't looked at what @Dancefortwo put up yet and maybe what I'm referring to is already being addressed. But I've never seen it.
There's no replacing what damage removed directly, but some damage could be repaired by contextual interpolation. Say two bars of Toscaninni's March 8 1953 performance of Beethoven's 5th at Carnegie Hall are irreparably destroyed. The tempo and style of the whole symphony could be applied to the missing bars such that any departure from the original would be negligible.
Today I'm sure we have the ability to make a film starring John Wayne at age 30 alongside Dallas Bryce Howard with a CGI John Wayne indistinguishable from the real John Wayne in manner and voice. The only thing preventing it is estate copyright. And sensitivity to good taste, but that's another argument.
