[PD] stereo difference?

[Scott R. Looney]

i think what Joe means by this is what is commonly referred to as a vocal
remover. meaning it takes out the center channel, and i believe that it's
done using M/S processing on the stereo signal. i can tell you it likely
won't involve CPU intensive tasks like FFT because they used to sell kits
to remove vocals in the 1980s:

http://www.paia.com/ProdArticles/vocalzap.htm

i might be misunderstanding but it sounds like that's what you're after.

scott


On Fri, Oct 12, 2012 at 10:55 AM, Joe White <white.joe4 at gmail.com> wrote:

> Ahh ok sure. Yeah you're right I think, it's annoying because in theory, L
> - R should give you what's *not* in the centre. But that ends up not
> being very useful anyway :)
>
> I'm no expert, but sounds like Mid-Sides could give you what you need,
>> no? then you can get rid of the Mid and *voilà* : sides.
>
>
> Eran, Mid-side is a different encoding to Stereo as you have 3 channels
> instead of 2, meaning the mono signal is already available.
>
> Cheers,
> Joe
>
> On 12 October 2012 10:49, i go bananas <hard.off at gmail.com> wrote:
>
>> oops, sorry about the double reply Joe, i forgot 'reply to all'
>>
>> to turn a stereo signal into a mono one, yes it's L+R..but that's not
>> what i wanted to do.  I wanted to take ONLY the parts of a stereo mix which
>> lie right in the middle.  It would be basically the inverse of a stereo
>> difference effect.
>>
>> To put it another way, Stereo difference removes those parts of the mix
>> which are panned dead center.  What i want to do is leave those parts, and
>> then remove anything that isn't panned dead center.
>>
>> At first, i thought it would be as simple as just subtracting the stereo
>> difference signal from the original mix.  But when i actually tried it, it
>> didn't work, and then also when i worked it out logically on paper, i
>> realized that it's impossible just with simple arithmetic.
>>
>>
>>
>> My best guess, is that you could FFT the stereo difference signal to get
>> it's spectral profile, and then subtract that from the original mix.  Might
>> give it a go some time.
>>
>
>
>
> --
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