Mid/Side on YouTube.
Hi, welcome to an episode of “Thinking Inside the Box” on Noah’s Ark. In the video, we’re gonna talk about a stereo miking technique called mid/side along with its corresponding processing in the box. This technique is a bit different from other stereo recording methods because it utilizes the stereo field in a different way.
Typically, one tends to think of a stereo signal as one left channel and one right channel. Consequently, a lot of stereo miking techniques try to mimic the configuration of our ears by treating the pair as L/R like in A/B or X/Y. However, there is another way called M/S or Mid/Side where the channels are split into whatever content that is common to both channels and whatever content that is different from both channels.
In the studio, you can record in M/S by using one Cardioid mic facing straight at the source and a figure-of-8 mic placed perpendicular to the source with the null point facing the source.
When listening to a recording made in M/S, the sensation tends to be different than L/R and it can sometimes produce this nauseous feeling of discomfort when the sides are more pronounced than the mids. This is also how stereo imaging plugins operate and is the result of too much widening.
The first time I heard this on a commercial recording was on an early version of James Taylor’s “Something in the Way She Moves” from his 1968 debut album. The vocals seem to be picked up mainly by the mid mic while the acoustic guitar comes in from the side mic. I was quite intrigued by that stereo image at the time.
The mathematical formula to convert from M/S to L/R and vice-versa is fairly straightforward. To convert from M/S to L/R, you sum the Mid with the Side to get the Left channel and sum the Mid with the polarity-reversed Side to get the Right channel. To convert from L/R to M/S, you sum the Left with the Right to get the Mid channel and sum the Left with the polarity-reversed Right to get the Side channel.
Some plugins allow you to process a stereo signal in M/S and this conversion is made internally but the signal still comes in and out as L/R. You can also use your regular stereo plugins in M/S and in the video, I show you how you can do that in any DAW.
To find out more about mid/side, you can watch the video above or on YouTube here.