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Subject:Removing music from a track
Posted by: farss
Date:9/8/2004 8:03:24 PM

Now before I get flamed, I have done a bit of research on this and yes this is a 100% legit project. Client has talking book material which it seems the vision impaired are having difficulty with because of the background music, no doubt added to the original mix for dramatic effect.
I understand that it MAY be possible to do the converse, remove a vocal from a track, I well understand the limitations of the process and why at best it's pretty marginal. I have read that the converse isn't possible but I'm having trouble getting my brain around the explaination.
I can't quite see why if I can get a music only track, inverting and subtracting that from the original will not remove the music. Quite possibly the client would be happy enough if all that was achieved was an improvement in the intelligability of the speech, some residual music would be acceptable. Of course I may be able to achieve much the same with some judicious Eq given that the vocal wouldn't have a wide spectral range.

Any advice much appreciated.

Ah, maybe the penny just dropped, the result of subtracting the speech would be a mono music mix and subtracting that from the original stereo music + vocal isn't going to work!

Bob.

Subject:RE: Removing music from a track
Reply by: MJhig
Date:9/8/2004 8:10:14 PM

Try the para-graphic EQ. Find the voice's dominant frequency probably starting at 1 kHz, adjusting the band probably 3 octaves. Then set up a low and high shelf and roll off the top and bottom part of the spectrum hopefully killing the music while saving the voice.

Don't compress as this will of course reduce the voice and raise the lower dB's, the music in this case if all goes as described.

MJ

Subject:RE: Removing music from a track
Reply by: farss
Date:9/9/2004 12:31:16 AM

Thanks,
that's about what i was going to try seeing as how there seems to be no magic way to make it disappear. Of course the client could just maybe find the original studio tapes and I could match those back for a 100% perfect result but this client and archiving don't seem to go together very well.

Bob.

Subject:RE: Removing music from a track
Reply by: Chienworks
Date:9/9/2004 5:24:04 AM

Assuming the original has stereo music + mono voice, the mix is (+Lmusic +Mvoice +Rmusic). If you remove the mono voice you get (+L -R). Subtracting the second from the first (+L +M +R) - (+L -R) = (+2R). So the best you can hope for is to eliminate one channel and double the other.

Considering the nature of the original project, i wouldn't necessarily expect the music to be stereo anyway. Even if it was stereo, the mix is probably more like (+Lmusic +Mmusic +Mvoice +Rmusic), with possibly some difference in the voice between the two channels. The real-world possibilites are much more complex than the ideal case.

edit.

Oooooooh, i just had a wicked afterthought. Perhaps you could do a mono voice-removed version that results in (+L - R) as above, mix that with the original to get the (+2R) track. Then mirror the whole process to get a (+2L) track. Then, combine those two mono tracks to get a new stereo track that is (+2L +2R), cut the volume in half to get (+L +R), invert it to get (-L -R), then mix that with the original so that you get (+L +M +R) + (-L -R), which should leave (+M). Of course, any real-world imperfections as mentioned above would still apply, especially any of the music that is panned center. Anything wrong with this logic? It's too early in the morning for me to be able to think straight enough to check myself, but i may set up a real-world test later on today and see what happens.

Subject:RE: Removing music from a track
Reply by: farss
Date:9/9/2004 5:42:04 AM

Interesting theory!
I suspect that although the music maybe stereo (haven't heard it yet!) it'll be a fairly narrow mix and one designed to work OK in mono as well.
Of course I'm also only guessing as to why the client wants the music out. The other possibility is they've gotten themselves into a spot with copyright. They probably bought the rights to the music for one medium and own the voice outright. Now maybe they want to release it in another medium and cannot or don't want to secure the rights to the music again. If that's the case I think they're out of luck as I'll certainly never get it out 100%, even to kncok it down a fair bit would have to do major damage to the voice.

Bob.

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