Stem Mixing

I am well aware it is standard practice to mix films in stems – its a simple matter of busing & monitoring the buses combined correctly. So for example when we final mix a film it is usual pratice to mix & record to at least four stems eg DIALOG 5.0 FOLEY 5.0 FX 5.1 & MUSIC 5.1

BUT I have been wondering how common is it to mix to stems when mixing music? So any music engineers/producers/mixers – how often do you print stems of your music prior to mastering? how many stems? do you do it all in one pass? multiple passes?

Usually when a composer delivers his premixed music to the mix stage for a films final mix, it is in the form of several stems eg as a minimum: Lead instruments 5.1, Percussion 5.1 and Supporting instruments 5.1 but my question is more relative to mixing music for its own sake eg making an album.

I mainly use ableton LIVE when writing/making music but much prefer to mix in ProTools so it seems like a very sensible way to get from one application to the other without using Rewire (which means losing VST plugs) or printing track for track & losing the feel of it….

Heres a few links I have been reading in the process of finding a good methodology for mixing my own music, but I’d appreciate suggestions from your own experiences…

Electronic Musician: divide & conquer provides some good tips re methodology
“Splitting your mix up this way gives you the flexibility to adjust the levels of the subgroups after the fact, making it possible to deal with most after-the-mix change requests….. The next thing you need to decide is what stems to make. Your decision might depend on which levels you’re most unsure of, or it might be linked to a particular musical style. Noted mixer and three-time Grammy winner Tony Prendatt suggests always doing a bass stem for R&B and hip-hop tracks since bass levels are so critical in those genres. In his most complicated mixes, Prendatt admits to preparing as many as ten stems, including separate string and horn stems….
In my experience, the most contentious issues in a mix are the vocal levels, so you will definitely want to create lead-vocal and background-vocal stems. From this point, you could simply create one more music stem that includes everything but the vocals, or you could separate the music further and create drum, percussion, bass, and instrument stems. Some situations might require even more divisions.
It’s best to create the instrument group by muting everything that’s not in the group, rather than by soloing things that are in the group (see Fig. 3). It might seem that soloing would achieve the same result, but unfortunately, all solo functions are not created equal. Some DAWs have a solo master that produces a different level from the master output; others change every soloed instrument into mono. Additionally, a soloed channel might not include the signal from the effects returns, depending on how the software is configured.
One thing to watch out for is the signal from prefader sends. If you’re muting tracks to isolate the ones targeted for a particular stem, and you’re hearing ghostly effects returns from tracks you thought you’d shut off, remember that the prefader effects live on after the track is muted, so you’ll have to turn off those sends as well…..”

tip#6 from sound bites dog
“Build-in safety mechanisms in case your listening/mixing environment is less than accurate…..mix stems (aka “seperation” mastering). Mix stems are usually 3 stereo tracks that contain groups of frequency-similar instruments. For exp: Stem 1 is all drums, percussion and their respective reverbs. Stem 2 is all vox, back ups, and their respective reverbs… Stem 3, gtrs, bass, keys, etc. The key to working like this and maintaining sync between the tracks is keeping the length, beginning, and end of your bounces the same. This mix option enables the mastering engineer greater flexibility…”

REEQ Mixing & Mastering
“A stem is a bounced audio file, containing a submixed group of audio material. for example, guitars, drums, or vocals. the majority of serious musicians these days can write, produce & mix their music from within a home project studio but don’t have the mixing experience or great outboard gear to make their mixes compete with professional mixers working in professional studios. by providing us with the multitrack stems, (normally 8 stereo files – guitars, bass, drums, keys, vocals, backing vocals, FX1, FX2) we can take your work to completion making use of the best eq’s, digital converters & audio summers available in an acoustically treated environment. we will maintain the identity of the original production but give it the extra polish that sets it apart.

& from the same source
Stem Preperation Procedure

1. do a great mix of your song – make sure you are happy with relative levels, panning & balance between instrumentation and vocals.

2. decide grouping of stems – the main consideration is to intelligently group instrumentation & sounds to give us the most flexiblity

example one: rock band – 8 stems

kick (mono)
rest of kit/percussion (stereo)
lead vocal (mono)
lead vocal fx (stereo)
backing vocals (stereo)
rhythm guitars (stereo)
lead guitar (mono)

example two: electronic club track – 12 stems

kick (mono)
loops (stereo)
percussion (stereo)
bass (stereo)
pads (stereo)
sound fx (stereo)
vocals (mono)
vocal fx (stereo)
backing vocals (stereo)
lead synth (stereo)
arpeggiated seq line (stereo)

3. bounce stems – bounce each one from exactly the same start point in order to ensure that they’ll all be in sync when lined up in our software program. we can accept wav, aif and sdII audio files at either a 16 or 24 bit depth. in the interest of keeping the quality as high as possible though, if your song was recorded at 24bit, bounce the stems at that bit depth, don’t bounce at 16 bit depth. we can accomodate sample rates from 44.1khz to 96khz.

4. please label all stems clearly

5 thoughts on “Stem Mixing

  1. Nottach

    I remember, back before I began my audio engineering “career” reading something, somewhere, about an audio format which included separate channels in the track/file that were each individual instruments/channels/stems. I remember a couple artists releasing albums with such files. I believe it was called mp3+? I’m not sure. But anyway, back to the topic at hand. When I mix, no matter what genre, I’ll create stems of each aspect, drums, bass, gtr, vox, etc. I find if I mix each instrument to a separate return/audio channel than at the end I can fit all instruments/ channels better into the mix. I like to dupe tracks and apply different settings to each then blend them into a bus. It just seems like thats the best way to mix to me, otherwise you’ve got to fight many channels instead of just the stem. Stems are key no matter what your gig may be.

  2. Nottach

    A little observation:
    On your Ex.2
    You’ve got Bass listed as (stereo).
    Have you had success with performing such an action?
    Especially for “Electronic Club”?
    I find that any time you’re mixing for large crowd in an enclosed, oddly-shaped, venue the best thing to do is make the bass as narrow as possible.
    After all, in that type of environment that’s the instrument driving the crowd.
    When the bass drops, or hits, that’s what they are listening for.
    So I say give it to them.
    As loud and clear as possible for that mix.
    Bass is key, clear, undistorted, compressed-to-hell, bass.

    Thanks for the topic. There isn’t much out there in the way of stems. I’ve got a few songs, public domain, as stems. I’d be glad to trade for whatever you may have. I find mixing stems to be fun and an experimental period. Sort of like remixing.


  3. tim

    Totally right Nottach, mono bass makes complete sense…
    in the world of film mixing where I observe the use of stem mixing all the time, when I provide bottom end sounds they are almost always mono but I leave it to the mixers to route them, as the .1 channel is LPF at approx 120Hz so its important bottom end goes to the main LCR speakers as well… they also, when appropriate, use sub enhancement to geenrate low bass/sub material from sounds that otherwise have none eg dbx subharmonic synth…

  4. Pingback: Watch your surrounding! Sound advice on audio formats (8 types + stems)

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