The mid-side technique is one of the most used tricks that helps correct the stereo sound image of the whole song, or individual elements in it. It introduces wideness, and you can find it in most compressor units as well within equalizers.
These days, many plugins can take an L/R signal and encode it to a Mid-Side (M/S) signal. As a result, this opens up different possibilities which are really useful, especially in the mastering process. Essentially, the Mid signal is the sum of the left and right channels summed to Mono, while the Side signal is the difference between Left and Right channels. In other words, everything that is different between the left and right channels.
In most cases, the right place for you to put your equalizer, exciter or compressor, which allows Mid-Side (M/S) processing, is the master bus. The reason for that is because all of your audio signals are summed together into the master bus. It goes without saying that in most cases you will have some instruments like bass, kick drum and snare positioned in the center. Instruments like guitar or synth leads are on the sides.
To start with the demonstration and present the changes in the overall stereo image I will apply this technique on the track previously made in SoundBridge.
The plugin unit that I have chosen for this demonstration is Bx_Control by Brainworx. It is a relatively simple plugin in which I can show you the difference between the mid, side and full stereo signals. Let’s begin by placing it on the master buss channel rack within SoundBridge.
You will notice the red arrow pointing to the Stereo width knob. This knob controls how much of stereo widening will be applied to the overall signal. Of course, if it remains unchanged, it doesn’t affect the signal. But moving it to the right, you will start to hear the mentioned effect. I am of the opinion that the sweet spot, in this case, would be around 200 %. Pushing it more could ruin the entire mix by bringing some of the instruments’ side signals to the extreme. This is something that I certainly don’t want to happen.
To sum up, let us listen to how the track sounds with the Bx_control bypassed, Mid signal soloed, Side signal soloed and in Full stereo. So try the Mid-Side technique for yourself, it helps a lot!
~ Bx_control bypassed
~ Mid signal soloed
~ Side signal soloed
~ Full mix