Understanding the Difference Between Multi-Track Parts and Stems in Music Mixing

The Importance of Clear Communication in Music Production

If a mix engineer as decorated as Bob Clearmountain is still having to say this out loud, you know it's a genuinely widespread mix-up, not just a pet peeve of mine. Bob posted about this a while back, visibly a bit exasperated, and a fair few of the industry's heaviest hitters piled on in agreement (CLA/Scheps). The distinction he was drawing is simple:

• Multi-track parts are the individual channels that make up a session.

• Stems are those channels sub-mixed down into groups that sum to make the mix.

  
  

One is the raw ingredient. The other is a partially cooked dish. Every few months, a client emails me to discuss mixing stems. We agree on a rate and timeframe that suits us both. What turns up is a Zip file with forty-something individual tracks: kick, snare, a few hat tracks, three synths playing the same part, two basses, lead vocal, fourteen backing vocal takes, FX sweeps, the lot. That's not stems. That's the multi-track parts. A mix may only bear 8-15 stems in total: drum stem, percussion stem, bass stem, brass stem, string stem, two synth stems, two guitar stems, lead vocal stem, backing vocal stem.

Why the Confusion Actually Costs You

This isn't pedantry for its own sake. If a client thinks they've sent you stems but they've actually sent you the parts, or vice versa, you can lose time on a project before anyone's even hit play. The parts need full mixing decisions: panning, EQ, dynamics, the works. A stem arrives with a lot of those decisions already baked in; you're now blending pre-cooked elements rather than building a mix from scratch. Confuse the two, and the mixer may have to do far more work than the brief called for, thus pushing your budget up. Bob's point wasn't "know your jargon for the sake of it"; it was "get this wrong, and it slows the whole session down."

The Benefits of Using Stems

What I love about stems is their ability to change the vibe of what the producer is going for. I was mixing a 70s soul-inspired track and just had no chance of recreating the drum sound the producer had. I didn’t have a clue what they’d done, but it sounded great. Instead of convincing the client my version was cleaner or more dynamic, I had the drum stem sent over and worked from that without needing to touch it at all.

Using a backing vocal stem can save hours of EQ’ing, fading, and automation riding. An FX stem with baked-in delays can maintain the producer's intention instead of sifting through a bunch of tracks trying to figure out why they don’t sound like the rough mix.

The Takeaway: Sending the Right Files

If you're a producer or artist sending work to a mixer, it's essential to understand the difference between multi-track parts and stems:

• Multi-track parts: Every individual channel, unprocessed or close to it. Send this if you want someone to build the mix from the ground up.

• Stems: Grouped, sub-mixed audio, such as drums, vocal groups, brass sections, or whatever the split may be. Send this if the balance is largely set and you need it to remain that way. This is great for saving time on the mix or going straight to mastering.

  
  

Get the terminology right with whoever you're working with before you export the session. It's a two-minute conversation. Bob's been doing this since the seventies, and he still thinks it's worth saying clearly, which tells you it's not a small thing.

Conclusion: Elevate Your Mixing Game

Understanding the difference between multi-track parts and stems is crucial for anyone involved in music production. By sending the correct files, you can streamline the mixing process, save time, and ensure your music achieves the polished, radio-ready sound it deserves.

With over 30 years in music production, I specialise in professional music mixing, vocal production, and mastering for artists, producers, and record labels. My personalised approach ensures each track achieves a radio-ready, streaming-optimised sound with exceptional clarity and impact, making your music competitive in the industry.

By mastering the terminology and ensuring clear communication, you can elevate your mixing game and achieve the best possible results for your projects.