Old 04-25-2018, 10:49 AM   #1
Rangler
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Default Mid Side phase cancellation

Is there a Mid Side Encoder Decoder that takes both sides and not just one side of the stereo field?

Center Canceler is doing the opposite and leaving only the center while deleting the sides.
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Last edited by Rangler; 04-25-2018 at 11:27 AM.
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Old 04-25-2018, 11:42 AM   #2
karbomusic
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What do you need to accomplish? If I just wanted to remove the center I'd load up JS: Mid/Side Decoder and pull the center slider down. I'm certain I don't understand the goal, so elaborate if you can.
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Old 04-25-2018, 12:17 PM   #3
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Originally Posted by karbomusic View Post
What do you need to accomplish? If I just wanted to remove the center I'd load up JS: Mid/Side Decoder and pull the center slider down. I'm certain I don't understand the goal, so elaborate if you can.
Using the MS En/De-coder … If you pull the center down, and the side is only taking information from 1 channel, when it decodes it, will it be true stereo or just a double of that channel?
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Old 04-25-2018, 02:19 PM   #4
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The side signal is L-R. It "takes from" both channels, but is summed (well, differenced) into just one. When decoded, you'll end up with L-R on one channel and R-L on the other, which will be all weird. There is no good way to get only the information unique to exactly one side in order to maintain the L/R separation and remove the center info. It just doesn't work that way.

There may be some fairly advanced algorithms out there that would do the job, but it would take some pretty heavy analysis and probably something like resysnthesis (fft etc).
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Old 04-25-2018, 05:07 PM   #5
Jason Lyon
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Mid-Side only has one "channel" for the Side bit - a recording from a laterally positioned figure-eight mic. It's the complex cancellation that gives the magic. A very beautiful idea...

Probably the best way to get to grips with it is to do it by hand - no decoder necessary. Duplicate the Side track, pan the two copies hard L and R, flip phase on one of them and fade them up or down as a pair.

Very crudely speaking:
Side pair right down, you just get the mono from the MID.
Start dialling up the Sides and you start filling out the width.
Mid right down and Sides right up and you've got a gaping hole in the middle.
Mid and Sides completely up and you've got a very wide sound but weak spots either side of the middle.

If you just want to widen a stereo track, there are emulators available, but it's a bit meh. Voxengo has a decent enough freebie called MSED that can seem to push sound out beyond your speakers. Most consumer TVs have something similar.
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Old 04-25-2018, 05:41 PM   #6
Rangler
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Quote:
Originally Posted by ashcat_lt View Post
The side signal is L-R. It "takes from" both channels, but is summed (well, differenced) into just one. When decoded, you'll end up with L-R on one channel and R-L on the other, which will be all weird. There is no good way to get only the information unique to exactly one side in order to maintain the L/R separation and remove the center info. It just doesn't work that way.

There may be some fairly advanced algorithms out there that would do the job, but it would take some pretty heavy analysis and probably something like resysnthesis (fft etc).
Quote:
Originally Posted by Jason Lyon View Post
Mid-Side only has one "channel" for the Side bit - a recording from a laterally positioned figure-eight mic. It's the complex cancellation that gives the magic. A very beautiful idea...

Probably the best way to get to grips with it is to do it by hand - no decoder necessary. Duplicate the Side track, pan the two copies hard L and R, flip phase on one of them and fade them up or down as a pair.

Very crudely speaking:
Side pair right down, you just get the mono from the MID.
Start dialling up the Sides and you start filling out the width.
Mid right down and Sides right up and you've got a gaping hole in the middle.
Mid and Sides completely up and you've got a very wide sound but weak spots either side of the middle.

If you just want to widen a stereo track, there are emulators available, but it's a bit meh. Voxengo has a decent enough freebie called MSED that can seem to push sound out beyond your speakers. Most consumer TVs have something similar.
Another user pointed me to a free VST called A1stereocontrol that seems to do what I want, as far as I can wrap my head around it. I'm not that bright. lol
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Old 04-25-2018, 06:01 PM   #7
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Quote:
Originally Posted by Rangler View Post
Another user pointed me to a free VST called A1stereocontrol that seems to do what I want, as far as I can wrap my head around it. I'm not that bright. lol
Hey, don't beat yourself up. Mid-Side is a concept that's as diabolically clever as it is useful. And, as I say, a very beautiful idea.
Most people have a problem wrapping their heads around the notion of polarity reversal (or "negative sound") at all, let alone how to work with it. All sound naturally involves phase cancellation on some level and I don't think I've ever met an engineer who doesn't resort to "suck and see" a lot of the time.
So don't feel bad. Glad you found what you needed anyway.
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Old 04-25-2018, 07:01 PM   #8
serr
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You can convert a stereo recording back and forth between LR and MS. All good.

As said, MS is a forward mono pickup and a figure of 8 side pickup (where the opposite side is opposite polarity).

When you convert LR to MS, you're not separating the mono from the stereo directly as you hear it. You're converting LR to MS. An odd perspective to the ear raw.

Maybe that helps?
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