Why you need Mid-Side Processing

What on earth is mid-side processing and why should you care? If you’re wanting your tracks to sound wider and richer then this technique could be the secret weapon to take your work to the next level. Interested? Read on!

Come on, tell me! What is mid-side processing?

Mid-side processing involves splitting your track into Mid (anything panned to the centre) and the Side (anything panning to the left or the right, grouped together). This enables you to have more control when applying effects and during mixing and mastering by giving you two separate processing channels rather than the traditional mono or stereo, where the processing is applied to the entire signal of the audio track.

The concept of Mid/Side Processing comes from a mic technique created by the English electromechanical engineer Alan Blumlein in the 1930s. His aim was to recreate how the human ear hears sound in stereo and was originally used to enhance the ‘space’ in recordings before stereo playback existed. The basic setup for recording in Mid/Side is one cardioid microphone to capture the mid and one bidirectional (figure-eight) microphone to capture the sides. When you listen to the cardioid mic you’ll get a mono signal, but when you combine it with the bidirectional mic, you’ll get an awesome stereo image, which you can make as wide as you like by upping the volume of the side channel.

I’ve not got the gear for this. What should I do?

Don’t worry! It’s possible to encode standard left/right stereo mixes to M/S and then decode it back to L/R using plugins such as Voxengo’s MSED and Kanaka MS Encoders that come with the open source music software Reason. Pro Tools Production have an awesome guide for decoding M/S recordings.

Where else can I find stuff on this?

There are loads of great tutorials and guides to using mid-side processing. Pro Audio Files have a great YouTube tutorial on mid-side EQ and compression. For you mastering enthusiasts, Tuts Audio have an awesome guide. If you really want to know all the technical details in depth then Hugh Robjohn’s article on stereo processing is particularly good. If you have any questions then let us know in the comments below.