Channel Tools - Mid/Side Encoders

olemon
I was watching a tutorial that used a Pro-Q2 and a Brainworx bx_controller V2, which the author called a Mid-Side Encoder, to analyze a reference mix.

 
I have a sneaking suspicion there is a question buried above, but I'm not sure what it is. I can however answer the next bit.

olemonIs Channel Tools a Mid-Side Encoder?  Is any plugin that has M/S processing a Mid-Side Encoder?  For example, I have a T-RackS3 Classic EQ that has M/S.

 
Channel Tools is a Mid-Side encoder. And any plugin that provides Mid-Side or M/S controls is encoding the Left and Right channels as Mid and Side. I don't own any T-Racks stuff, but if it say it has M/S then it probably does.
 
In case Mid-Side itself has you perplexed...
 
"Normal" stereo recordings have two channels, left and right. Most of the time this is sufficient, but over the years (and we're talking the beginning of Stereo FM broadcasting, so that's a lot of years) there have been applications where left and right channels were not sufficient to preserve the stereo image.
 
Some clever engineers figured out that they could use a matrix to encode and decode the channels so that the mono signal was preserved, and that timing errors between the two channels were minimized. (The timing problem was a real challenge for early stereo broadcasters, and especially those awful broadcast "cart" machines, among others. Oh yeah, that would include the infamous long playing record!)
 
Enough history!
 
The MID channel is the sum of the left and right channels, or all the content.
 
The SIDE channel is the difference between the left and right channels, and for the most part represents the spatial localization information. It is trivial to decode (or encode for that matter) to switch between the two formats.

To convert from L+R to M/S:
route your left and right channels to a single buss - call that MID
route your left channel, and a polarity inverted copy of the right channel to a second buss - call that SIDE
 
To reverse the process:
route MID and SIDE to a single buss, and call that LEFT
route MID and a polarity inverted copy of SIDE to a second buss and call that RIGHT
 
It's a good idea to use channels and busses to get a feel for the process and how it works, but you can also use the included Channel Tools for the same result.

This matrix approach has many applications - Mid/Side and Blumlein microphone configurations are one example, and the old Sonic Hologram (or whatever Carver and Polk called their respective products) is another.
 
Where we use it most, I'd guess, is for signal processing. Compressing the MID while leaving the SIDE alone creates a very different effect than compressing left and right. The same applies to equalization, reverb, even delays and modulated delays. The beauty of MID/SIDE encoders is that once you've encoded you can use the rest of your processors in their old-fashioned configurations - as long as you remember what you did<G>!

Does that help?