Think you know everything there is about mixing in stereo? Think again. FabFilter has published an excellent three part video series produced by Dan Worrall titled How To Mix In Stereo Without Sucking In Mono. This series is extremely well presented explaining stereo mixing fundamentals, panning, stereo microphone placement, phase, the effects of comb filtering, width, mono compatibility and more.

These three videos make up nearly an hour of watch time and, in true Dan Worrall style, explains every topic in ways which are easy to understand and apply.

If you are serious about recording, mixing or mastering these three videos are by far some of the best tutorials you can watch during lockdown. Given that more and more people listen to music on single speaker solutions that sum the left and right sides together it’s important to know how stereo works and how to check and address mono compatibility.

Part 1: Toeing The Blumlein

When panning a mono part left or right you change only the levels feeding the left or right channels, this doesn't introduce timing or phase differences. Likewise if you record stereo signals with a coincident microphone pair, signals arrive at both microphones at the same time and in phase. This avoids the worst possible mono compatibility issues but still doesn't provide perfect mono compatibility. This tutorial shows the pitfalls that remain and looks at a few ways to use panning and effects to create a sense of width, while mostly following Alan Blumlein's original rules and avoiding any timing differences between the channels.

Part 2: Timing, The Secret Of Great Stereo.

Timing differences between the left and right channels can sound great in stereo and as a bonus will also seem much more spacious on headphones, but you need to be careful about mono compatibility. This episode explains what happens when you delay one channel by a tiny amount ("Haas delay"), what then happens when you sum them to mono ("comb filtering"), and shows how to use the technique in practise without creating mono compatibility issues.

Part 3: Fantastic Phase

Haas delay is not the only way to create phase differences between left and right channels. Filters and EQ can be used to create a sense of width or depth, or you can double track the part, or create unison synth layers. This episode looks at a few of these techniques and their implications for the mono downmix, and shows the awesome power of mid/side EQ on stereo sub mixes.