PreSonus Blog

Friday Tip – Mid-Side Processing Made Easy

Mid-side (M-S) processing encodes a standard stereo track into a different type of stereo track with two separate components: the left channel contains the center of the stereo spread, or mid component, while the right channel contains the sides of the stereo spread—the difference between the original stereo file’s right and left channels (i.e., what the two channels don’t have in common). You can then process these components separately, and after processing, decode the separated components back into conventional stereo.

Is that cool, or what? It lets you get “inside the file,” sometimes to where you can almost remix a mixed stereo file. Need more kick and bass? Add some low end to the center, and it will leave the rest of the audio alone. Or bring up the level of only the sides to make the stereo image wider.

The key to M-S processing is the Mixtool plug-in, and its MS Transform button. The easiest way to get started with M-S processing is with the MS-Transform FX Chain (Fig. 1), found in the Browser’s FX Chains Mixing folder.


Figure 1: The MS-Transform FX Chain included with Studio One.



The upper Mixtool encodes the signal so that the left channel contains a stereo file’s center component, while the right channel contains the stereo file’s side components. This stereo signal goes to the Splitter, which separates the channels into the side and center paths. These then feed into the lower Mixtool, which decodes the M-S signal back into stereo. (The Limiter isn’t an essential part of this process, but is added for convenience.)

Even this simple implementation is useful. Turn up the post-Splitter gain slider in the Center path to boost the bass, kick, vocals, and other center components. Or, turn up the gain slider in the post-SplitterSide path to bring up the sides, for the wider stereo image we mentioned.

Fig. 2 shows a somewhat more developed FX Chain, where a Pro EQ boosts the highs on the sides. Boosting the highs adds a sense of air, which enhances the stereo image because highs are more directional.


Figure 2: The Image Enhancer FX Chain.

In addition to decoding the signal back to stereo, the second Mixtool has its Output Gain control accessible to compensate for any level differences when the FX Chain is bypass/enabled. Also, you can disable the MS Decoder (last button, lower right) to prevent converting the signal back into stereo, which makes it easy to hear what’s happening in the center and sides.

And of course…you can take this concept much further. Add a second EQ in the center channel, or a compressor if you want to squash the kick/snare/vocals a bit while leaving the sides alone. Try adding reverb to the sides but not the center, to avoid muddying what’s happening in the center. Or, add some short delays to the sides to give more of a room sound….the mind boggles at the possibilities, eh?


Download the Image Enhancer FX Chain here! 

  • smpiggy

    Thank you Mr Anderton, its my honor too. Sorry for delay to reply, I’ve just finished my vacation recently. I’m very proud you like China and our people, and our food too(surprised me you’ve visited China twice), and I promise your name and your site will be always put in the head of any article when I translet to Chinese.
    😊Thank you again, you are so kind!

  • I would be honored to have my articles appear in China. I have visited your country twice, and found the people very warm and friendly (and the food is fantastic, too!). You have my permission to translate any of my Presonus tips into Chinese.

  • smpiggy

    Yes, I’m now learning on it. and Mr Anderton, do you mind if I translate your article in Chinese to spread out these Powerful skills of StudioOne?
    I claimed credit to you and the link to here at the 1st place.

    here is link:

    StudioOne is getting more popular in China, and your articles are very helpful for people to find out the magic of it.

  • smpiggy

    You’re welcome, I see Marcus video alot too, very cool, its great to have skillful tech masters like Craig and Marcus to lead us find out StudioOne. Cheers!

  • The splitter’s killer feature is the multiband crossover.

  • Sounds to me like a “Channel Editor 101” tip might be a good idea.

  • I know where it is, just not how to use it but Marcus Huyskens just posted a blog with info. Thanks for taking the time to help me out. J

  • smpiggy

    Thank you Craig, its a great tip, you can do alot with splitter!

  • smpiggy
  • Just trying to find info on how to use the Channel Editor……..I don’t get a lot of time to explore the software trial and error wise.

  • It depends on where you have your presets. The simplest option is to open the Browser, go to the Effects tab, look for the FX Chain folder and a sub-category folder. Open the folder, then right-click on one of the FX Chains and choose “Show in Explorer” to see the folder that contains it. Place the preset file in the same folder hierarchy. Circle back and let us know if this works or not 🙂

  • Doug Lyons

    Thanks Craig…great tips.
    Where do I place this preset file once I download it?

  • Anderton

    Yes, Studio One sure has a lot of cool stuff hidden in various corners 🙂 I’m working on a tip for this Friday that I think is pretty cool…

  • Donnie Hart

    Once again, you demonstrate how handy Studio One can be!

  • Anderton

    What is the problem? Does the download not work?

  • Hi – I can’t seem to find how to use the Channel Editor like the image. I like the MS potential for widening mixes or bigging up the centre. Thanks for the tips!