Tools for isolating center (not just MID)

VST, AU, etc. plug-in Virtual Effects discussion
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Scarlet Pumpernickel
KVRist
156 posts since 30 Jul, 2017

Post Mon Jun 01, 2020 4:16 am

Hello. Does anybody happen to know a tool that could isolate a center signal in a stereo program; in other words a signal that is exactly the same (including level) in both channels. I suspect Leapwig StageOne could do it, but unfortunately even with current sale it's out of my budget.

Thank you.

EDIT: After cursory glance, I no longer think StageOne can do this.

DarkStar
KVRAF
9559 posts since 2 Sep, 2003 from Surrey, UK

Re: Tools for isolating center (not just MID)

Post Mon Jun 01, 2020 4:33 am

I thought that centre would be the same as mid. Can you clarify the difference?
The 'Mid' channel contains just the information that appears in both the left and right channels, and the 'Side' channel contains all the information that differs between the left and right channels
The Mid channel is the center of a stereo image. When the Mid channel is boosted, the listener perceives a more centered (mono) sound to the audio. The Side channel is the edges of a stereo image. When the Side channel is boosted, the listener perceives a more spacious (wider) sound to the audio.
And, what will you want to do with the isolated audio? Many plug-ins have MID/Side mode of operation. And some can process MId only, passing on or muting Side.
DarkStar
Interesting, if true ...

User avatar
Scarlet Pumpernickel
KVRist
156 posts since 30 Jul, 2017

Re: Tools for isolating center (not just MID)

Post Mon Jun 01, 2020 4:49 am

I'll try to clarify. Side channel is everything that is "out of phase" in two channels; Mid channel is everything else. For example, take mono snare track and pan it in the center then take mono guitar track and pan it far right; now solo the MID - you'll get snare at the same level and guitar but lower in level - that is the MID track. In that example I want to get just the snare track. Hope that explains it.

DarkStar
KVRAF
9559 posts since 2 Sep, 2003 from Surrey, UK

Re: Tools for isolating center (not just MID)

Post Mon Jun 01, 2020 5:15 am

Ah ha, thank you. So you are after the centre-panned audio?

How about the MeldaProduction multiband plug-ins, with the crossover mode set to Panorama?
-- the "centre" band spread can be adjusted, soloed, have its level changed.

Or, perhaps, "Mid/Side" crossover mode would be better.
Panorama crossover is another specialized tool, similar to the level crossover; it splits the signal into bands according to the panorama. If, for example, you create 3 evenly spaced bands (100%L to 33%L, 33%L to 33%R, 33%R to 100%R), then the leftmost band will contain mainly the signals located in the left speaker, the rightmost band will contain mainly signals from the right speaker and the middle band will contain centred signals. Please note that this doesn't mean the crossover attempts to analyze the space the signals are coming from and send them to the respective bands, which is probably what your brain would attempt.

This crossover is useful only when processing stereophonic (or surround, in which case the channels from 3 upwards are kept intact) signals and can be used for all kinds of mixing and creative processing. For example, using a multiband compressor with this crossover can be used to effectively control the stereo image as each band would be processing a different part of the stereo image. To mention another example, a multiband delay or reverb can be used to produce a different ambience for different parts of the stereo image.

Mid/side crossover is similar to panorama crossover, but it splits the signal according to their position in mid/side location. In other words, the more to the left a band, the more centred is the signal in it. Similarly the more to the right a band, the more "to the side" is the signal in it. You can think of it as the panorama view folded back on itself, around the center position. If, for example, you create 3 evenly spaced bands (centre to 33% L or R, 33% L or R to 67% L or R, 67% L or R to 100% L or R), then the leftmost band will contain the centred signal, the rightmost band will contain the signals to the extreme left or right and the middle band will contain signals in between. It can be used for similar tasks as the panorama crossover.
DarkStar
Interesting, if true ...

TIMT
KVRian
742 posts since 8 Mar, 2009

Re: Tools for isolating center (not just MID)

Post Mon Jun 01, 2020 5:25 am

Leapwing Audio Centreone is the only thing i know that does this and Waves Central,but the latter has weird artfefacts.theres a teeny amount of group delay or some kind of smearing with th Leapwing one but its honestly barely noticeable IMO
I

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Scarlet Pumpernickel
KVRist
156 posts since 30 Jul, 2017

Re: Tools for isolating center (not just MID)

Post Mon Jun 01, 2020 5:58 am

Thank you both DarkStar and TIMT, I'll take a look.
@TIMT I see now that I confused Centreone with StageOne; also I believe, you meant Waves Center?

GRUMP
KVRist
443 posts since 11 Jun, 2019

Re: Tools for isolating center (not just MID)

Post Mon Jun 01, 2020 6:10 am

I don´t really know/care about the Difference between Mid/Centre, but Voxengo´s MSED (free) is one of those little Helpers that I don´t want to miss in my Toolbox.

It mainly offers seperate Levels for M/S and works on Voxengo-Level.

An other Tool that comes to my Mind is Blue Cat´s MB-7. You can widen or shrink the Signal-Width here.
Always on the Run ... :wheee:

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Scarlet Pumpernickel
KVRist
156 posts since 30 Jul, 2017

Re: Tools for isolating center (not just MID)

Post Mon Jun 01, 2020 6:29 am

MSED is always on my master channel (for true mono monitoring), but it's not that kind of tool.

MogwaiBoy
KVRAF
3539 posts since 26 Nov, 2015 from Way Downunder

Re: Tools for isolating center (not just MID)

Post Mon Jun 01, 2020 5:40 pm

Sounds pretty near impossible. Mid = Center = Mono.

Side channel is not just simply things that are out of phase. Mono instruments can be panned, exist in the "side channel" but still be mono, and not out of phase at all.

Maybe RX or some kind of advanced offline process?

Bouroki
KVRist
418 posts since 16 Jun, 2013 from Morocco

Re: Tools for isolating center (not just MID)

Post Tue Jun 02, 2020 2:20 am

MogwaiBoy wrote:
Mon Jun 01, 2020 5:40 pm
Sounds pretty near impossible. Mid = Center = Mono.

Side channel is not just simply things that are out of phase. Mono instruments can be panned, exist in the "side channel" but still be mono, and not out of phase at all.

Maybe RX or some kind of advanced offline process?
It does exist but AFAIK it's an FFT-based process that's bound to be full of artifacts and is more useful for stuff like extracting specific frequency ranges like vocals etc...

TIMT
KVRian
742 posts since 8 Mar, 2009

Re: Tools for isolating center (not just MID)

Post Tue Jun 02, 2020 5:29 am

Scarlet Pumpernickel wrote:
Mon Jun 01, 2020 5:58 am
Thank you both DarkStar and TIMT, I'll take a look.
@TIMT I see now that I confused Centreone with StageOne; also I believe, you meant Waves Center?
My bad yeah that's the one.long time since i used it but i distinctly remember it having too many FFT like artefacts on the attacks.Centreone is almost entirely indistinguishable from the source :tu:
I

fese
KVRian
1231 posts since 14 Sep, 2004 from $HOME

Re: Tools for isolating center (not just MID)

Post Tue Jun 02, 2020 5:42 am

MogwaiBoy wrote:
Mon Jun 01, 2020 5:40 pm
Sounds pretty near impossible. Mid = Center = Mono.

Side channel is not just simply things that are out of phase. Mono instruments can be panned, exist in the "side channel" but still be mono, and not out of phase at all.

Maybe RX or some kind of advanced offline process?
I was being sceptical, too. What we call “center” is in the end an acoustic illusion by our brain that interprets signals arriving at the same time in our ears from two speakers as “coming from the center”.
What is commonly called M/S should correctly be called sum/difference (M/S is a stereo recording technique).
But that center one seems to manage it. I wonder how they do it, my idea would have been a) some FFT mangling or b) machine learning where you learn to separate the instruments. Both prone to artifacts.

User avatar
Scarlet Pumpernickel
KVRist
156 posts since 30 Jul, 2017

Re: Tools for isolating center (not just MID)

Post Tue Jun 02, 2020 8:18 am

Bouroki wrote:
Tue Jun 02, 2020 2:20 am
It does exist but AFAIK it's an FFT-based process that's bound to be full of artifacts and is more useful for stuff like extracting specific frequency ranges like vocals etc...
That actually is what I need it for. I need to "salvage" the old track where the backing instrumental is skewed to one side (and quite f__ked up) but vocals are dead center; and I also have the original instrumental track. There's also some clock drift involved so I wasn't able to just "null".

In any case, I tried CentreOne and indeed it gave me a more narrow slice than just MID but still not good enough for my current needs. I'll try Waves Center next (I'd never thought Waves Center would do something that advanced).

I also tried "Music Rebalance" in iZotope RX and it worked better in my case; I think I'll try Deezer algorithm next, as in my recent experience it's markedly better than the one iZotope has.

Again, thank you all for the suggestions!

Bouroki
KVRist
418 posts since 16 Jun, 2013 from Morocco

Re: Tools for isolating center (not just MID)

Post Tue Jun 02, 2020 12:25 pm

Scarlet Pumpernickel wrote:
Tue Jun 02, 2020 8:18 am
I'll try Waves Center next (I'd never thought Waves Center would do something that advanced).
Waves are pioneers and true experts at what they do. One would not think so going by audio forums nowadays :lol:

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consordini
KVRist
310 posts since 6 May, 2020

Re: Tools for isolating center (not just MID)

Post Fri Jun 05, 2020 7:26 am

^ It is a weird balance of support and critique (sometimes just blind hate) - which is completely understandable. But without actually frequenting forums, you usually only hear raving reviews.
Take care :wink:

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