Hi List, I am trying to extract a drum loop from a soundfile, which has a violin loop mixed in. Earlier in the song I got a clean pass of the violin with by itself. I was wondering how I could change the phase of the violin loop by 180 degrees so that when I mixed it in [+~] with the other sample the violin loops would cancel eachother out. Leaving only the drum loop. Does anyone know how to do this with pd? Or any other programs/plug-ins?
B~ www.cypod.co.nr
If it's exactly the same, you should be able to just use [-~] on the unaltered signals. Phase cancellation would only work for a handful of frequencies at a time. If it's not exactly the same sound, it'll be pretty complicated. Sometimes if you check out how it was mixed, you find one part is lower on one side or the other. If the violin's mostly on the left, try just the right track, unless your drum loop is stereo.
On 8/4/06, beau c cypod25@gmail.com wrote:
Hi List, I am trying to extract a drum loop from a soundfile, which has a violin loop mixed in. Earlier in the song I got a clean pass of the violin with by itself. I was wondering how I could change the phase of the violin loop by 180 degrees so that when I mixed it in [+~] with the other sample the violin loops would cancel eachother out. Leaving only the drum loop. Does anyone know how to do this with pd? Or any other programs/plug-ins?
B~ www.cypod.co.nr _______________________________________________ PD-list@iem.at mailing list UNSUBSCRIBE and account-management -> http://lists.puredata.info/listinfo/pd-list
On Fri, 4 Aug 2006, beau c wrote:
I am trying to extract a drum loop from a soundfile, which has a violin loop mixed in. Earlier in the song I got a clean pass of the violin with by itself. I was wondering how I could change the phase of the violin loop by 180 degrees so that when I mixed it in [+~] with the other sample the violin loops would cancel eachother out. Leaving only the drum loop. Does anyone know how to do this with pd? Or any other programs/plug-ins?
Chances are that it won't work because the violin isn't played in exactly the same way. If the violin wasn't sampled and replayed exactly the same, it won't work. Each manually replayed violin note will have different timing and thus a rather random phase difference from the original one.
a 180-degree phase shift is [*~ -1].
there's a shortcut for both that and a [+~], called [-~] (duh)
therefore, a 180-degree phase shift can be computed efficiently using only the right inlet of [-~].
to do phase-insensitive cancellation you'd need more complex tools, like [fft~] and such, unless I'm missing something.
_ _ __ ___ _____ ________ _____________ _____________________ ... | Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju | Freelance Digital Arts Engineer, Montréal QC Canada
On 8/5/06, Mathieu Bouchard matju@artengine.ca wrote:
On Fri, 4 Aug 2006, beau c wrote:
I am trying to extract a drum loop from a soundfile, which has a violin loop mixed in. Earlier in the song I got a clean pass of the violin with by itself. I was wondering how I could change the phase of the violin loop by 180 degrees so that when I mixed it in [+~] with the other sample the violin loops would cancel eachother out. Leaving only the drum loop. Does anyone know how to do this with pd? Or any other programs/plug-ins?
Chances are that it won't work because the violin isn't played in exactly the same way. If the violin wasn't sampled and replayed exactly the same, it won't work. Each manually replayed violin note will have different timing and thus a rather random phase difference from the original one.
If it's a loop, though, and *if* the loop is exactly the same by itself as it is mixed, wouldn't the only differences be from resampling and maybe interpolation? If so, that's probably imperceptible.
-Chuckk
On Sat, 5 Aug 2006, Chuckk Hubbard wrote:
If it's a loop, though, and *if* the loop is exactly the same by itself as it is mixed, wouldn't the only differences be from resampling and maybe interpolation? If so, that's probably imperceptible.
Differences from resampling/interpolation will be noticeable, else it wouldn't be possible to notice the effect of interpolation, and thus interpolation would be useless. So chances are that in the difference you'd hear exactly the hiss that interpolation was removing from the sound.
If you're stuck with that hiss, just say something about residual music and postdigitalism, so that it seems intentional.
_ _ __ ___ _____ ________ _____________ _____________________ ... | Mathieu Bouchard - tél:+1.514.383.3801 - http://artengine.ca/matju | Freelance Digital Arts Engineer, Montréal QC Canada