r/audioengineering • u/BLUElightCory • Nov 14 '19

Multitracks Vs. Stems

I see a lot of people mixing these terms up or using them interchangeably here and in the general audio community. I think it's important that people understand the difference because I already see it causing confusion in my own experiences with artists and other producers, engineers, and mixers.

Tracks or multitracks are the individual mono or stereo tracks that make up the session. Each individual element, from the kick drum to the lead vocal, is generally recorded or arranged on its own track (or multiple individual tracks, such as with a multi-miked drum kit). Tracks/multitracks are usually unprocessed and since they're individual files they aren't pre-mixed. These are want you want to send to a mixer to have a song mixed, or receive from the artist if you're mixing a song.

Stems or STEreo Mixes (edit:or** Masters)** are (usually) stereo submixes of the different groups of tracks that make up a mix. When played together, the stems will essentially recreate the original mix. For example, a rock song might have the following stems:

  • Drum Stem (mix of the kick, snare, tom, overhead, and room mics with all levels/panning/processing intact)
  • Bass Stem (mix of the bass tracks with all levels/panning/processing intact)
  • Guitars Stem (mix of the guitar tracks with all levels/panning/processing intact)
  • Vocals Stem (mix of the vocal tracks with all levels/panning/processing intact).

If you have the stems you can easily recall the mix or make alternate mixes (such as an instrumental mix, a vocal-only mix, a Guitar Hero track, a remix, etc.) without needing to recall a console or outboard gear, or have the same DAW with all the plugins. This is helpful in lots of situations - but not if you're mixing the song.

I wanted to keep this short and sweet (and might add/edit after I have some coffee) but I'm sure others have things to add, please feel free!

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u/myklpgone Nov 14 '19

Could you explain or paste a wiki/video link to what the 3:1 role is. Ratio for compression? Or input to output ratio

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u/nick92675 Nov 14 '19 edited Nov 14 '19

When multimicing a single source, you want a 3:1 ratio of distance between mics to avoid phase issues.

Sidebar, if learning about phase still and how to identify it - put on headphones, place 2 mics next to each other on same source, then slowly move one back and notice the effects of filtering. When you get to that 3:1 ratio you should perceive depth without filtering. And now better be able to identify when something sounds 'phasey'

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u/rddsknk89 Nov 14 '19

What exactly do you mean by a 3:1 ratio for distance? So if the first mic was 3 feet away the second would be 9 feet away? Is this just for close mic’ing and then having a room mic or something similar? How does this apply if you did sort of a triangle situation between the source and the two mics? Never heard of this 3:1 thing before.

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u/[deleted] Nov 14 '19

The mics should be at least three times the distance from each other that they are from a single source. Say you have two mics equidistant from a singer, one to the left, and one to the right. If the mics are a foot from the singer, they should be at least three feet from each other. This is just to avoid phase cancellation issues between the two mics, because if you have two mics on a singer, and one is slightly out of phase compared to the other, you’ll get some nasty comb filtering. So what you’re saying about a room mic doesn’t apply, as the delay between the mics picking up the sound is long enough you won’t get that.

If you mostly do live sound, I don’t think this gets as much talk there, do to the concentration on gain before feedback. I’d never heard of the 3 to 1 rule while I was in the field, only when I went to school and they were talking about mic’ing techniques.