Prepare for STEM Mastering

How to prepare a mix for STEM mastering.


Back in 2014 we wrote this blog  ‘Stem Mastering Vs Stereo Mastering’ – we get a lot of requests around STEM mastering, so here’s our top tips on how to prepare a mix for STEM mastering.


What are mix stems?

Mix stems are basically bulk parts of songs. You might group together all the guitars and bass, all the the drums, all synths and all vocal parts, for example.

All stems will contain processing, so all reverb, delay or compression will be left on the stems.

Why would you use stems?

It does offer more flexibility. If the mix (of all stems) is a bit peaky and the levels are a bit off, then an engineer has the flexibility to change that.

But, there is a difference between mixing stems, and mastering from stems.


What’s the difference?

Mixing from stems is exactly what is sounds like. Your mix engineer will mix your track from a bounce of bulk sections. There are pros and cons with doing this. As a mix engineer, their flexibility is seriously reduced, and they may not get the best results. On the other hand, you will probably get a mix done much quicker, and will probably save you a bit of cash.


Mastering from stems is a little different.

As ever, there is always confusion around mixing stems and mastering stems. Some engineers might do both, they might mix the stems and then add some processing to the master buss so that you then get a louder/compressed overall mix. But this way is still not really mastering from stems.

The clear difference with mastering is that the engineer won’t really mess with anything, unless truly necessary. Sometimes engineers might cut the end of a song and drop it a few dB so it sits nicer at the tail of a track. It’s in that way that the mastering engineer will use the stems. Mastering from stems gives an engineer the best way to make small adjustments to levels. A mastering engineer won’t make any huge adjustments to your mix, like changing processing, messing with mix EQ, or reverb.

How should I prepare my mix stems for mastering?


The most important thing first of all is that you are happy with how your track is sounding. Whether you have mixed it or you’ve had the stems mixed elsewhere, make sure the track/s sit well with you first. This is the most important part.


So, once you’re happy.


  1. Get your mix engineer (or yourself) to split up your tracks into sub-groups. These could be as simple as drums, guitars & bass, vocals, keys, effects etc. You can be as granular as you need to be, but be aware that this is for mastering.
  2. Remove any master buss processing. Be aware that if there has been processing during the mix or stem mix, removing this will change the sound. Make sure that the mix is completed with no compression on the master channel.
  3. Solo all the tracks that are going to be added into the group. If you’re bouncing down the drums first, make sure all drums are soloed, all room mics are soloed and that any other percussion is there too.
  4. Bounce the soloed tracks. Make sure you follow a simple naming convention with these too. Save all of these ‘sub-groups’ of tracks into a folder together.
  5. Repeat step 4 for all of the other ‘sub-groups’.
  6. Check all the files.
  7. Drop all files into a DAW and compare the original mix. This way you can check if anything is missing, or if it doesn’t sound how it should.
  8. Send them to your mastering engineer.

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