M‑S miking is easy to set up, offers plenty of options at mixdown, and has some unique advantages over other stereo arrays. So if you've not yet tried it, why not give it a go?
Most SOS readers will have heard of Mid‑Sides (M‑S) recording, but I suspect many will have shied away from actually trying it. Perhaps the idea of creating a 'decoding matrix' triggers a brain freeze, and it all sounds too complicated? Well, it really isn't, and I'd urge everyone to try it. In fact, M‑S is one of the most flexible and forgiving stereo recording techniques, making it really beginner-friendly.
You don't need particularly expensive gear, and free plug-in decoders mean you no longer have to create a 'matrix' yourself. You can dial in as much or as little 'room' as you want, during or after recording. And if you screw it up or you simply don't like the room sound you captured on the day, you're left with a perfectly good mono recording — which is more than can be said for many other stereo recording techniques.
In this article, I'll set out in simple terms what gear you need, how to set it up for good results, and how you might manipulate the sound after recording.
Mid‑Sides isn't just a recording technique, it's a whole different way of looking at stereo. But it's not hard to get your head around. Like standard Left‑Right (L‑R) stereo, Mid‑Sides uses two channels. But instead of one carrying a signal for the left speaker and another for the right, one (the Mid, or 'M' channel) carries the information that's common to the left and right sides, while the other (the Sides, or 'S') carries information about what's different between left and right. In practice, the level of the Sides signal determines how wide the sound is when played back in L‑R stereo, and also the amount of room ambience in the decoded signal. If you monitor in mono, all you'll hear is the Mid; your Sides signal disappears completely.
Mid‑Sides miking is suitable wherever you'd normally use a coincident array — such as an X‑Y crossed pair, or a Blumlein array (crossed fig-8 mics pointing left and right). There's nothing wrong with those techniques, and they all share the same advantage over spaced arrays in that they inherently have a stable stereo image, but M‑S recording can neatly side-step some of the disadvantages of those other coincident formats.
First, when using any X‑Y or Blumlein array, sources in the centre of the sound stage don't hit either mic on-axis, so they'll be subject to the off-axis coloration inherent in directional mics (their off-axis response is generally less sensitive to high frequencies, typically delivering a 'darker' sound than intended). In M‑S recording, sound at the centre of the 'stage' will hit the Mid mic on-axis, usually resulting in a cleaner capture of the centre, and a cleaner mono sound. This could be...