What is mid-side?

[Mercury1650507370]

I guess a more relevant question is, what are the differences between left and right panning vs. mid-side?

 

What audible differences can be distinguished between left, right, panning as opposed to m/s processing?

 

In what instances is m/s used more effectively instead of simple panning?

[triplets]

Check it out:

 

https://en.wikipedia.org/wiki/Stereophonic_sound#M.2FS_technique:_mid.2Fside_stereophony

[stardustmedia]

MS has nothing to do with panning. MS and LR are different ways to describe or how to split up stereo signals.

 

 

Here's a simple description:

 

LR: Is the simple way, all people know. L contains the signal for the left speaker, R for the right speaker.

MS: Is different. The stereo signal is split up into the Mid signal and the Side signal. Mid contains ONLY the information that will be in the middle of your left and right speaker (so it's the same signal with the exact same volume on both speakers). The Side contains only that is different from that Mid signal. The Side is the content, that is not the same on both speakers, thus creating width and space.

 

Further information about MS when you DO NOT CONVERT it back to LR: Mid is completely mono and 100% mono compatible. While Side is not mono compatible, but will even be completely "deleted" when LR is played back mono.

 

So, panning on:

LR: Distributes the energy between those both speakers. Very simply put. So panning to the left decreases the energy on the right side, giving you a left panned signal, because L is now louder than R.

M: Pans the Mid signal across the LR stereo buss (master buss, master out). The Mid signal is a perfect mono signal, so that narrow little point will be panned to the left/right, the same way as panning LR above.

S: Will pan the stereo width in total, means panning to the left, will decrease the width on the right side.

[Mercury1650507370]

Thanks Trip. Great resource, trying to digest this, and actively reading it.

 

Deft, using the tools in Logic how are the differences between the sides drawn out to be heard in a mix? By EQ'ing?

 

In other words, I can imagine two unique frequency responses being captured an XY pair of cardioid mics that produce a left, center and right, but then, how are the sides isolated, then brought up in the mix using the tools in Logic?

[David Nahmani]

I can imagine two unique frequency responses being captured an XY pair of cardioid mics that produce a left, center and right

A pair of XY cardioid mics do not produce a left, a center and a right. Electrically, it is only two signals: left and right. Acoustically, it produces a stereo field that has a 60 degree width.

 

how are the sides isolated, then brought up in the mix using the tools in Logic?

Insert a Channel EQ, set "Processing" to "Side only" and raise the Gain slider to the right in the Channel EQ.

[stardustmedia]

See David's comment. I'd just like to add, take care of the mono compatibility if you raise the sides, resp. drop the mid. The sides themselves will be completely removed when played back in mono. So a signal where you raise the sides, and thus get a nice wide sound, may loose too much in mono.

[Mercury1650507370]

David, Thanks for the pointer to the Logic tool and setting needed to adjust the side audio. Thanks deft, on checking for mono compatibility.

 

Lesson Learned. Use the Logic Channel EQ, and set to Side Only. For me, the "Side Only" setting is easy to contrast using "Mid Only."

 

This only leaves the other question I had regarding the audible differences between L/R panning and the sides. The difference I perceive in the sides as opposed to L/R panning is like pole shifting the phase of the audio to obtain that sound. Is that right? How can the audible qualities of side EQ'ing be properly described? Apologies in advance. I know this is a deep question, but it will help me to learn how and why to use it in practice.

[stardustmedia]

Just to make sure, there is no side-panning. You create the side this way:

 

Make signal mono = Mid

Duplicate the original track, phase revert the right side

The difference between phase-reverted R and L = Side

No difference = pure mono signal

 

Technically correct MS encoding:

Mid = (left + right) –3dB

Side = (left – right) –3dB

 

Technically correct MS decoding:

Left = (mid + side) –3dB

Right = (mid – side) –3dB

 

 

I'm not sure, what happens (how it sounds) when panning a mono sound to the left/right. I think it will get louder the more you pan on one side (and it shouldn't matter to which side). Even more unsure what happens to stereo sounds that are panned with the different pan laws available in Logic.

 

Can't test now, but you can try this: Set the master buss to sides-only, so you hear only the side signal. Then start panning a mono and a stereo signal. Test with a stereo signal that has easily recognizable different sounds on each side (L and R).