splitting channels in LEFT - MID - RiGHT possible?

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orionka
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splitting channels in LEFT - MID - RiGHT possible?

Post by orionka » Tue Sep 26, 2017 8:16 am

Hey guys,

I'd like to split a stereo signal in the following way:
- (1) only signal of left channel
- (2) any signal that is on both channels = mid content
- (3) only right channel

example for a mono sound:
signal is panned hard left - there is only sound in (1)
signal is panned 50% to the left - there is sound from (1) and (2)
signal is mono content left in the center - there is only sound in (2)

I wonder if this is possible for the mid channel.

What comes to mind is to use utility and make the spread zero.
However, if I take a signal that is hard panned to the left, it just takes the sum of both left and right and I still can hear the signal as mono in the center, even if this is per definition no mid-content at all.

Any ideas? I tried around with phase cancelation but didn't come to a solution yet.

This has a real world idea behind it, so no mind game at all. :)

chrk
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Re: splitting channels in LEFT - MID - RiGHT possible?

Post by chrk » Tue Sep 26, 2017 9:13 am

(1) and (3) are easy with the Utiliy: just use its Channel Mode chooser to let only left or right get through. This will now be a mono signal you'll hear in the phantom centre, so use the Utility's panning to move it left or right respectively.
orionka wrote:I wonder if this is possible for the mid channel.
in stero there is no mid channel, just the phantom centre.

Good luck chasing a phantom.

You may try constructing an effect rack with two parallel chains*, both carry a Utility, both in stereo channel mode, both centred, one at 100% width, the other at 200% width width (i.e. the difference between l and r), then switch the phases to subtract the difference.

No idea if it works, I can't try right now.

*You may want to both turn chain volumes down by 6 dB.

orionka
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Re: splitting channels in LEFT - MID - RiGHT possible?

Post by orionka » Tue Sep 26, 2017 10:01 am

The Left and Right are really no problem.
What you suggested was my second guess...
In this way I still get the hard panned mono signal coming through the mid channel.
But thanks for your idea!

Your are right with chasing a phantom, but if you can define it, then you should be able to separate this, too.

There is a lot about Mid-Side Processing and some Plugins offer also Decoding a Stereo-Signal into Mid-Side.
An Utility effect rack should do the thing. But I don't know how at this point.

I think, it must be possible. It would be really nice to have this in my arsenal.

Khazul
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Re: splitting channels in LEFT - MID - RiGHT possible?

Post by Khazul » Tue Sep 26, 2017 6:15 pm

Probably the best hack you could easily do in Live is with two utility plugins:

One set to 0% width - that feed the center speaker (strictly this would be a mid signal - not an N channel center signal).
The other inline with your stereo out set to say 150%+ which will pull down the mid in the stereo pair, but will probably leave the stereo image a bit wierd - worth a trey though.

Proper stereo to N channel up-mix conversion often involves quite complex processing and so a specialize plugin would be needed to do the kind of up-mix you get in a modern AV amp for eg, the stereo to 7.1(.2) that many modern AV receivers have for playing music around all your speakers.


Recently I was thinking of dabbling in surround sound mixing as I have a reasonable surround AV amp and speakers on it, but the only way to get a surround signal into it is via digital surround encoding over optical/coax or HDMI. It all came crashing to a halt when I discovered that it would probably be cheaper to buy a new high end AV amp with analog surround ins than buy a friggin plugin to do the real time dolby digital encoding :(
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Stromkraft
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Re: splitting channels in LEFT - MID - RiGHT possible?

Post by Stromkraft » Tue Sep 26, 2017 8:26 pm

orionka wrote:
I'd like to split a stereo signal in the following way:
- (1) only signal of left channel
- (2) any signal that is on both channels = mid content
- (3) only right channel.
Waves Center is not like all other mid/side solutions in that the mid doesn't have to be the sum of left and right. It also can retain panned instruments in the stereo image. You can get it currently for $26.10 with the below link. I'd suggest you try the demo first and experiment with it.
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orionka
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Re: splitting channels in LEFT - MID - RiGHT possible?

Post by orionka » Wed Sep 27, 2017 8:04 am

wow! thanks for the hint regarding the waves plugin.
It does exactly what I'd like to do. I tried it with a hard panned signal.
There is no mid-signal coming trough until I pan it towards the mid.

I consider it.

But for the purpose of understanding and problem solving:
this must be possible with Lives native devices, too.

Any idea? I would prefer a DIY/native solution within an audio effect rack.

Thanks so far to both of you.

[jur]
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Re: splitting channels in LEFT - MID - RiGHT possible?

Post by [jur] » Wed Sep 27, 2017 11:14 am

Just go for the Waves Center plugin.
I've always wish I could do it with native Live devices (or M4L) as I try not to rely on 3rd party plugins, but this is a very tricky DSP wizzardery.
Frankly I don't even know how it is achieved, and I've studied the topic and tried for a loooong time.
Not so long ago Center was the only plugin (I think) that could do that, but a few weeks back I've read somewhere that there's a new guy in town that does the same thing... Unfortunately, I can't remember the plugin's name, but you can get Center for very cheap.
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orionka
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Re: splitting channels in LEFT - MID - RiGHT possible?

Post by orionka » Wed Sep 27, 2017 11:41 am

Thanks for this insight.
This Plugin is not really CPU-heavy but I notice an increase in latency even when Live shows just 1 ms.
I tried to avoid turning off Latency compensation for this current setup.
It is interesting to see that it must be a more complicated operation than simple + and - operations with phasing.
I wonder if I can catch the process of the plugin with an impulse response.
I'll try that later.

fishmonkey
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Re: splitting channels in LEFT - MID - RiGHT possible?

Post by fishmonkey » Wed Sep 27, 2017 12:07 pm

it's definitely not something you can achieve with routing and phase inversion.

there are also a few other plugins that do stereo manipulation with more sophisticated techniques, including:

http://quikquak.com/prod_UpStereoPro.html

http://www.airwindows.com/wider/

https://www.nugenaudio.com/stereoizer-s ... -au-vst_23
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Stromkraft
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Re: splitting channels in LEFT - MID - RiGHT possible?

Post by Stromkraft » Wed Sep 27, 2017 9:33 pm

orionka wrote: But for the purpose of understanding and problem solving:
this must be possible with Lives native devices, too.
I think it's like attempting to recreate Surreal Machines "Magnetic". You think you can do it and you spend weeks on it until you realize it's not worth the effort. I tried that for a collaborator that didn't have it.

The reason I got Center is because panned instruments largely stay panned, unlike common mid/side solutions that actually mix left and right. Personally I only do mid/side treatment for certain tracks that need this and I use Center on the master buss. One of those subtle things that do so much for a mixdown.

I adressed this previously in 2015 here in Collapse bass to mono alternatives (non m/s).

Member Angstrom made a very nice blog post about mono safe bass. I'd argue this is an alternative and not a replacement for what Center offers. I believe TDR Slick EQ M may do something similar as well, but I haven't tried this one yet.
Last edited by Stromkraft on Thu Sep 28, 2017 7:36 pm, edited 1 time in total.
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Angstrom
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Re: splitting channels in LEFT - MID - RiGHT possible?

Post by Angstrom » Thu Sep 28, 2017 12:50 am

you just reminded me- I needed to put the warning in about phase issues when using crossovers!

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