Isolate sound mostly heard in one channel

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tkrackers
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Isolate sound mostly heard in one channel

Post by tkrackers » Wed Jun 03, 2009 5:02 pm

Is there a way (I'm sure there is) to isolate a sound that is mostly heard in one channel?

Basically I have a song that has some slide guitar that is heard "louder" in the left channel. Now if I want to pull just that from the recording I should be able to do that with some splitting of tracks and inverting (or similar things) right? It seems possible, but I just can't seem to wrap my head around how to do it.

Does anyone understand what I mean, and can explain how I would do this. As I write this it almost seems like this should be very easy, I just can't figure it out.

Thanks in advance!!!

steve
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Re: Isolate sound mostly heard in one channel

Post by steve » Wed Jun 03, 2009 5:17 pm

You can't exactly "isolate" it unless the rest of the recording is identical on both left and right channels, which it almost certainly will not be.
What you can do however is to use the channel with the louder slide guitar for both left and right.

Using Audacity 1.3.7

Split the stereo track (click on the track name for the drop down menu)
Delete the track without the slide guitar.
Duplicate the remaining track (Ctrl+A then Ctrl+D)
From the drop down menu on the upper track, select "make stereo track".
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

kozikowski
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Re: Isolate sound mostly heard in one channel

Post by kozikowski » Wed Jun 03, 2009 6:29 pm

And if the real complaint is the show is louder on the left than the right, you can fix that with the amplify controls while you have the left and right split. Then recombine into stereo.

Koz

tkrackers
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Re: Isolate sound mostly heard in one channel

Post by tkrackers » Wed Jun 03, 2009 6:47 pm

Thanks so far on this. The first idea kind of works but isn't really what I am looking for.
I'll mess around a bit more with this and post anything that I figure out.

I am still open for any other suggestions as well.

steve
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Re: Isolate sound mostly heard in one channel

Post by steve » Wed Jun 03, 2009 6:59 pm

tkrackers wrote:The first idea kind of works but isn't really what I am looking for.
I thought that may be the case. You are looking for the effect that extracts a whole banana from a banana milkshake.

The best that can be done to date is using the (non-free) VST plug-ins "ExtraBoy" or "VoiceTrap". After a lot of fiddling with the parameters, my tests with these produced a kind of banana like mush - not bad for a task that was just impossible a couple of years ago, but the extracted banana mush was not very appealing.

If the music that you are working on has just the right characteristics and you have the patience to tweak it enough it is possible to get pretty good results (check out their demos for examples).
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

tkrackers
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Re: Isolate sound mostly heard in one channel

Post by tkrackers » Thu Jun 04, 2009 2:23 am

I guess I just thought that since the slide guitar is predominately in the left channel I could just subtract the frequencies that exist in both the left and right channels from each other (invert?) and then extract the center only (the center-pan remover) , leaving me with the "leftovers" - the slide guitar that isn't the same in the left channel.

I guess it just doesn't work that way...

steve
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Re: Isolate sound mostly heard in one channel

Post by steve » Thu Jun 04, 2009 4:10 pm

Well yes it could work that way, but it is extremely unlikely to do so. The reason being that for the "invert and mix" method to "cancel out" the other sounds, they must be identical in left and right. If the other instruments were placed in the centre of the room and a stereo pair of microphones was used to record them, you might expect the two microphones to pick up the exact same signal, but they won't. The signals recorded by each microphone will be very slightly different, and that's enough to stop it from working properly, though you may still get some degree of cancellation - you'll have to try it to see how effective it is.
9/10 questions are answered in the FREQUENTLY ASKED QUESTIONS (FAQ)

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