Hi list, i was wondering if there is any "stereo difference" object or abstraction if not how can i achieve this effect in pd?
thanks
R.
it's ridiculously simple.
you just. invert one channel [*~ -1] and then mix them both together as one.
if anyone knows how to get just the MONO component of a signal, i'd love to know. I have a feeling you need to do FFT analysis and reconstruction for that though
i go bananas wrote:
if anyone knows how to get just the MONO component of a signal, i'd love to know. I have a feeling you need to do FFT analysis and reconstruction for that though
Look how mono turntables are compatible with stereo vinyl records. This might help :)
Isn't a Mono signal just L + R?
If you're worried about phase cancellation I would say the fault lies with whoever mixed it.
Cheers, Joe
On 11 October 2012 07:58, Charles Goyard cg@fsck.fr wrote:
i go bananas wrote:
if anyone knows how to get just the MONO component of a signal, i'd love
to
know. I have a feeling you need to do FFT analysis and reconstruction
for
that though
Look how mono turntables are compatible with stereo vinyl records. This might help :)
http://en.wikipedia.org/wiki/Vinyl_disc#Stereophonic_sound
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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.
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.There are plenty of tutorials on how to do that. Or no? Date: Fri, 12 Oct 2012 18:49:58 +0900 From: hard.off@gmail.com To: white.joe4@gmail.com CC: pd-list@iem.at Subject: Re: [PD] stereo difference?
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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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@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.
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@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@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.
-- Follow me on Twitter @diplojocus
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