Mid Side processing in Ableton

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brian sansone
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Mid Side processing in Ableton

Post by brian sansone » Wed Jul 14, 2010 2:34 am

Is there a way to take a mono or stereo audio track and turn it into a Mid Side set up?

Thanks
Brian

HJYoung
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Re: Mid Side processing in Ableton

Post by HJYoung » Wed Jul 14, 2010 2:41 am

http://emusician.com/mag/emusic_front_center/

Read this. You may want to first gain a basic understanding of what Mid side really is and how to use it. It can be a wonderful tool for controlling the stereo image.

luddy
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Re: Mid Side processing in Ableton

Post by luddy » Wed Jul 14, 2010 5:44 am

You can do this with the Utility plug-in using two tracks that are being fed by the same stereo signal. In one track, set width to 0, that gives you L+R (M) on both channels. In the other track, set the width to 200% and flip the phase of one of the channels. That gives you L-R (S) or R-L (-S). I don't know the 'polarity' of their width control so I don't know which. If you put them back together as below and L and R are reversed, it means that you should flip the phase on the other channel instead when creating S.

To reverse it, you have to first create (M-S)/2 (L) and (M+S)/2 (R). M-S is flip the phase on both sides of S and mix with M, which can do by feeding both M and flipped S to the input of a single audio track. Before or after mixing them together, you need to apply -6dB of gain to get the "/2". M+S is just the mix of M and S, with -6dB gain. Finally, you have to put L and R back into a single stereo track. To do this, pan L all the way left, pan R all the way right and mix them into a single audio track.

There are probably better ways to set up all the routing. You could probably set something up with return channels and sends that would save some of the extra plumbing.

-Luddy

garyboozy
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Re: Mid Side processing in Ableton

Post by garyboozy » Wed Jul 14, 2010 8:20 am

EQ8 has an MS mode too. very handy.

subunit23
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Re: Mid Side processing in Ableton

Post by subunit23 » Wed Jul 14, 2010 11:32 am

There are probably better ways to set up all the routing. You could probably set something up with return channels and sends that would save some of the extra plumbing.
m/s processing is done exactly as luddy said but can be done within racks very easily, so once you setup everything you can save your rack and re-use it very quickly.
i even think there is a m/s rack included in live 8 but i have to check.

naph
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Re: Mid Side processing in Ableton

Post by naph » Wed Jul 14, 2010 12:37 pm

create a rack
make two chains
in the first chain put an utility at 0%, followed by the effects you need for the mono part of the signal
in the 2nd chain put an utility at 200%, followed by the effects you need for the stereo part of the signal

i don't think the 0%, 200% trick gives you an exact 'SIDE' signal (i.e that can be reversed using a standard M/S encoding algorythm) but indeed allows you to separaterly processing the mono and the stereo components of the original signal.

tried the phase cancelation test, summing a normal track and the track with this rack, and i got 100% silence, so i assume it just works.

that's what i use in my mastering projects.

3dot...
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Re: Mid Side processing in Ableton

Post by 3dot... » Wed Jul 14, 2010 1:54 pm

EQ8 m/s mode
Image

luddy
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Re: Mid Side processing in Ableton

Post by luddy » Wed Jul 14, 2010 2:42 pm

naph wrote:create a rack
make two chains
in the first chain put an utility at 0%, followed by the effects you need for the mono part of the signal
in the 2nd chain put an utility at 200%, followed by the effects you need for the stereo part of the signal

i don't think the 0%, 200% trick gives you an exact 'SIDE' signal (i.e that can be reversed using a standard M/S encoding algorythm) but indeed allows you to separaterly processing the mono and the stereo components of the original signal.
If you flip the phase on one of the channels in the 200% width utility, you get exactly the side signal (in both channels). The 200% output has the left channel exactly the inverse of the right channel; if you put a correlation meter on it you will see it pegged at -1.

-Luddy

brian sansone
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Re: Mid Side processing in Ableton

Post by brian sansone » Sat Jul 24, 2010 2:32 am

quote="HJYoung"]http://emusician.com/mag/emusic_front_center/

Read this. You may want to first gain a basic understanding of what Mid side really is and how to use it. It can be a wonderful tool for controlling the stereo image.[/quote]


Why the polarity shift for one side?
Do you know any other good links where I can learn a about polarity and/or other basics?
The article was definitely enlightening.
Thanks
Brian

evon
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Re: Mid Side processing in Ableton

Post by evon » Fri Jul 30, 2010 8:38 pm

Remember that one of the channels (left channel)of the "S" (side) is positive (polarity) and the other is negative. So, in other words, polarity is just another term for "phase".

The part of the wave above the zero line is positive and the part below is negative. Remember that inserting the Utility Plug in the track would make both channels in the track mono (positive). Therefore, to get the negative polarity required for Mid-Side, the phase on the right channel is inverted.

So in a sense we now have three channels a mid ("M") or mono channel and one positive and one negative side channels.

Hope this helps, I am learning a lot here myself.
fe real!

Vass
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Re: Mid Side processing in Ableton

Post by Vass » Fri Jul 30, 2010 9:21 pm

Mr Bill has a good tutorial on this:

http://www.mrbillstunes.com/post_20100624.php

evon
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Re: Mid Side processing in Ableton

Post by evon » Fri Jul 30, 2010 9:32 pm

Yes that was good. It gave me some new perspectives.
fe real!

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