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Re: Newbie questions
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Re: Newbie questions


  • Subject: Re: Newbie questions
  • From: Brian Willoughby <email@hidden>
  • Date: Sat, 4 Apr 2009 14:04:12 -0700

It's a bit misleading when folks refer to this sort of thing as 'phase' - a more appropriate term would be 'polarity.' Only a pure sine wave has a 180-degree phase shift when it's polarity is inverted, but any changing waveform will obviously not have its features shifted in phase at all, because they remain at the same precise time.

To get to your question, you basically subtract the two channels. Using 'minus' is the same as reversing polarity of a channel.

Be warned that this effect produces a mono output from a stereo input, and it does not cancel stereo reverb effects on the center channel vocals. It will actually mix the reverb from both channels, potentially making it louder. In other words, this is a very easy effect, OUTPUT=LEFT-RIGHT, but you'll end up with a mono song with ghostlike vocals remaining, unless there's no reverb or purely mono reverb in the original.

It should be a fun first project, though.

Brian Willoughby
Sound Consulting


On Apr 4, 2009, at 11:55, James Cicenia wrote: I need to make a voice remover. I have been looking around and it seems that I can do a left / right channel phase operation to remove the center channel vocals which is good enough for me.

Being absolutely new... I would appreciate any code, examples,
tutorials or things to read that could help me get started.

This will be for the iPhone.

thanks
James Cicenia

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References: 
 >Newbie questions (From: James Cicenia <email@hidden>)

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