> the really difficult part is the separation of a chord, where you have
> to look at base frequencies and find out which overtones belong to which
> groundfrequency. with strings and maybe also with other instruments you
> can predict the overtones and use this information to grab the correct
> frequencies for shifting...
Yeah, I'm betting this works really well for harmonic sounds but I guarantee there are musical signals where it will fall apart. Like many-layered noisy pitched percussion with inharmonic spectrum.
I like that quote "I began to see that what doesn't work in theory can still work in reality." A lot of times people think because a problem is really, really hard or because it is "theoretically impossible" that no solution can be found. There are always heuristics and approximations! In the past I worked at a company that made a good deal of money selling software that solved a problem that is theoretically proven to be impossible to solve with a computer. In the context of software, theoretically impossible (i.e. incomputable) just means you cannot solve the problem with 100% accuracy. It doesn't mean you can't solve a problem with 95% or even 99.99% accuracy if you take lots of educated guesses...
Must say i was pretty impressed, and i'm not even into audio editing. There must be situations where this doesn't work perfectly, such as me adding really soft overtones..but the examples were pretty convincing.
And i have my doubts about the next phase of their plan...
I've searched google for more about it, and found a video interview (soundonsound.com) with the guy who invented it. It seems that one of the problems of this technology is that can't divide instruments playing the same note.
Probably because it makes some kind of analysis based on tonic-overtones to extract the sound, so it's pure logic: same note, same overtones (more or less).
I might have listened bad (view the video and correct me if so) but the guy said that this plugin also eliminates noise from the audio. It makes sense, because it doesn't belong to music overtones, so it could be filtered out, or recognized as another source and deleted.
Great program by the way, shame it won't sale until end of the year :( (at least)