Whether you’re trying to widen your image or want to introduce a unique form of processing to your mix, mid-side is a crucial element. Mid-side processing can be introduced with the right EQs and can be included in your routing to allow for mid-side saturation, compression, and more.
What are Mid and Side?
Whenever you have a stereo signal with variation between the left and right channels, we can create a mid-side track. In short, the mid image is everything that is identical between the left and right, and the side is everything that is different between the 2.
You can create a side image by inverting the phase of one channel in a stereo track. This will nullify everything about the 2 signals that are identical, leaving behind only the differences.
Alternatively, you can just use this MSED plugin by Voxengo, since it’s free and more straightforward.
Let’s take a quick listen to mid and side images.
Mid-side EQs make it easy to affect the mid and side separately – one of my favorite uses is to make the lows mono by using a high-pass filter on the side image. Another is boosting 2.5kHz on the mid-image to make the vocal cut through in a master.
As you can imagine there are a lot of possibilities, but one more popular use is expanding the high frequencies with a side-image high shelf.
Let’s take a listen to these 3 filters being enabled.
Easy Mid-Side Routing
Sometimes you’ll want to process a signal as mid-side, but the plugin doesn’t offer it. When I come across this issue I just duplicate the channel and use MSED on both, with one instance isolating the mid image, and the other isolating the side image.
I think some DAWs offer more options for this type of routing, but if yours doesn’t, this is a good alternative.
Let’s listen to mid-side processing being performed with this routing, and with a plugin that’s typically not capable of affecting the mid and side separately.
Mid-side saturation isn’t too common, but it definitely has its uses – Saturn 2 is one of the few plugins that allow for it, but let’s use the routing from the last chapter so that we have more plugin options. With this PSP saturator, I’m going to saturate the mid-image.
I’ll use something that emphasizes my lows, in turn making the low frequencies more centered. On the side image, I’ll saturate some of the higher frequencies, causing expansion to my highs.
So as you can see, we can use this setup and the harmonics caused by saturation to affect our stereo image in a unique way.
Let’s take a listen.
Mid-side compression is a great way to cause dynamic stereo expansion – whenever the mid-image is compressed more than the side, the image will sound wider. This is usually the cause since the mid image is more powerful than the side, triggering the compressor more often.
This effect works well on drums, vocals, and on full mixes and masters if used subtly. Let’s take a listen to it on a full mix with some more aggressive settings so it’s easier to hear.
Creative Temporal Mid-Side
This is a fun use of mid and side in my opinion – in short, I’ll use one type of delay or reverb on the mid image and a different type on the side. This can be practical – for example, I could do this to drum overheads, giving the side distinct stereo imaging.
Or it can be creative if I use a harmonizer on a vocal’s mid-image, and reverb on the side.
Let’s take a listen to it on drums.
Side Image Transients
One of my favorite ways to process the sides is with a transient expander – this is especially true from drums since it adds a needed and often lacking percussive quality to the sides. I’ll use the same setup from chapter 2 and insert Punctuate to expand the image.
Then I’ll blend the effect to ensure it’s not too aggressive. Let’s take a listen.
Mid-Image Parallel Processing
Similar to last chapter, parallel compression and distortion work well, but this time on the mid-image. I’ll use the Invigorate plugin by NewFangled audio to introduce compression, limiting, and overdrive to my mid-image and then blend the effect in with the mix dial.
I find this works well on drums as well, but can also be great on various instrument buses.
Let’s take a listen.
Transient and Tonal Mid-Side
Next, I’m going to try something unique and insert this Split EQ onto a signal’s mid and side image. So now my signal is split up into mid and side, and the mid and side are individually broken up into tonal and transient elements via the SplitEQ.
I’m sure this could lead to phase issues if I’m not careful, but with some carefully dialed-in settings, we can get a lot of control over the side with this routing.
Let’s take a listen to these EQs being used this way.
Creative Mid-Side Automation
One last thing to keep in mind with mid and side is that the channels can be automated to create really unique effects. We could do something simple like automate the mid image’s volume down and the side’s up to cause increasing expansion or something more aggressive like affecting panning.
What I’ll do instead is automate various levels of saturation on the mid and side to dynamically change their timbres and the width of the stereo image.
Let’s take a listen to it.
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