Two quick questions for clarification.

[scottel]

Hey alll

ive just been reading a post on ehre about mixing and there are a few techniques mentioned that im a little unsure about and im wondering if you guys could help me out understanding what they do and what to look out for?


Mid/Side processing? is this done via a vst plugin or is it just terminology for processing each side of the spectrum?

Phase correlation? I can remember watching the Andi vax mixing vid where he uses the waves analyser plugin to check out if the sound was hiting in the anti phase area. he then used a stereo imaging plugin to narrow the spread.
Should i be doing this on all my sounds?
If this is the case, then wouldnt applying a stereo widener just cause the phase to go nuts?

Could anyone advice on how i should use these tools in mixing and whatto look out fo to consider using ?

Hope you guys can clear this up

Scott

[Keith99]

You need a MS capable plugin. It splits the stereo signal into mid, which is right + left and side which is right - left. You can then process them separately. You can use mid side processing to help with stereo spread by cutting cutting low frequencies from the side channel i.e. making them dead centre. Stereo wideners do indeed cause a lot of trouble phase wise and I tend to not use them

[scottel]

thanks for that keith, any recommendable mid side plugins?

[Keith99]

I like Pro-Q, I believe most FabFilter plugins have mid/side processing. Other EQs do as well like IEQPro

[BertKoor]

Mid/Side processing? is this done via a vst plugin or is it just terminology for processing each side of the spectrum?

It's origin is quite old. The usual way of storing stereo material in a DAW and on tape is using discrete channels for left and right. However vinyl records and FM radio work differently. Both stemmed from techniques that were originally mono only, and expanded to stereo in a mono-compatible way. There's a mono signal being the "mid" channel, and the "side" channel contains the difference between left & right. With some extremely simple "calculation" the discrete left & right channels can be derived:
* Left = Mid + Side
* Right = Mid - Side

And it also works vice versa:
* Mid = Left + Right
* Side = Left - Right

In the analog world you get the Side channel when the ground is cut from both left & right connectors.

In MP3 files it's a common technique also to store the Mid channel and encode Side seperately in a much lower or variable bitrate.

Anyway, in a DAW MS-processing is useful to do different things to the Mid & Side channels using a pair of MS plugins and a regular stereo plugin (or two different mono plugin instances) inbetween. EQ, compression... the sky is the limit.

Some useful plugins:
http://www.kvraudio.com/product/3809
http://www.kvraudio.com/product/4023

Phase correlation?

An extension to mid-side, based on phase correllation is invented by Dolby Labs:
http://en.wikipedia.org/wiki/Dolby_Surround
http://en.wikipedia.org/wiki/Dolby_Pro_Logic

If you play a stereo mix with phase issues through a home cinema set with Dolby decoding, then some parts (eg reverbs) will come from the back channels.

The most simple thing to do is to check your mixes in mono. Parts with phase issues will sound softer than intended. Only then it's time to take action. If you care...

[scottel]

very informative, thankyou very much for taking the time to help