Type how many stems for mixing into a search bar and you mostly get shrugs. It depends, ask your engineer. It really does not. For an automatic mixer, and honestly for most human engineers too, one rule settles nearly every case: export one stem per musical role. Not one per microphone, and not one per section. For most bands that lands between 8 and 14 files.
The two ways bands get stem exports wrong
The first failure mode is exporting too little. A single stereo bounce feels tidy, but every balance decision is baked into it forever. If the guitars bury the vocal in that file, the vocal stays buried. Bandmixr cannot fix it either; it has no stem separation feature, and while AI splitter tools exist, what they pull out of a bounce is a smeared, artifact-laden approximation, never your original tracks. A stereo file can be mastered, but it cannot be mixed, because mixing means balancing separate parts and the bounce just deleted the separation.
The second failure mode is the opposite: dumping every raw mic track into the upload. Picture a folder of 24 files: three are the same guitar amp captured by different mics, the bass shows up twice as a DI and an amp signal, and the drum kit alone eats eight slots. Those duplicates are not separate musical parts. The blend between two mics on one cab is a tone decision you already made at the session, and handing it off unresolved means something else re-decides your sound. Human engineers push back too: roughly 24 tracks is where many ask you to bounce groups down, and some charge per stem, so duplicates cost real money.
The rule: one stem per musical role
Quick terminology first, because these words get swapped constantly. Multitracks are the raw individual recordings, one file per microphone or input. Stems are groups of those tracks printed down to single files. What a mixer needs sits between the two, and What Are Stems and Why Do They Matter untangles it properly.
For export night, the definition is simpler. A role is any part someone in the band might want louder or quieter on its own. The lead vocal is a role. The bass is a role. Each guitarist's part is a role. The third mic on the guitar cab is not, it is a flavor of a role that already exists. The test: would you ever grab a fader for this alone? Nobody wants mic two on the amp louder while mic one stays put. You want the guitar louder.
Every file you upload becomes one voice in the mix. Bandmixr analyzes each stem for loudness, frequency content, dynamics, phase, and clipping, then builds the hierarchy, EQ, panning, and clash resolution around those voices. A part trapped inside a bigger bounce cannot be balanced on its own, and a part smeared across three files gets treated as three things when it is one. What Happens to Your Stems Inside Bandmixr walks through that pipeline step by step.
Drums: split the kit or bounce it?
The kit is where the question gets real, because a typical close-miked kit is about eight microphones by itself: kick, snare top and bottom, rack tom, floor tom, two overheads, and a room mic. You do not want eight drum stems. You also do not want one.
The sweet spot is four: kick on its own, snare with both mics printed together, the toms as one file, and the overheads plus room mic as one stereo file. The kick earns its own stem because kick and bass fight over the same low frequencies, and clash resolution can only carve them against each other if the kick arrives as a separate file. In a small KVR production forum poll, three quarters voted for separate drum tracks, and the strongest argument was the kick: compress the whole kit as one file and every kick hit pumps the cymbals along with it. How to Mix a Full Band From Stems goes deeper on why that kick-versus-bass slot decides the whole low end.
Now the honest tradeoff. A well-balanced stereo drum bounce still works. If your drummer plays an e-kit with a stereo output, or the recorder only handed you a kit mix, upload it as one drum stem and the song will still come together. What you give up is precision: the engine treats the drums as a single voice, so it cannot duck the bass against the kick or lift the snare without lifting the cymbals. Acceptable, not ideal. Do not re-track a good take just to split it, but if you can export the kick separately, do.
What to merge before you export
Everything with multiple captures of one part gets printed to a single file. Two mics on a guitar cab: blend them and export one stem. Bass DI plus bass amp: pick the blend you like, one bass stem. A double-tracked rhythm part can go out as one stereo file with the doubles inside. Two guitarists playing different parts always stay separate, because those are two roles, not two flavors. A stack of six backing vocal takes is one role, so bounce it to a single stereo stem. And never export both a group and the tracks inside it, or the same audio arrives twice.
Real stem counts for real lineups
A trio with one guitar, bass, drums, and a singer lands at seven or eight stems with a split kit. A four-piece with a second guitarist and some gang vocals sits around nine or ten. For a five-piece rock band with keys, the folder looks like this:
- Kick
- Snare
- Toms
- Overheads and room (stereo)
- Bass
- Rhythm guitar 1
- Rhythm guitar 2
- Lead guitar
- Keys
- Lead vocal
- Backing vocals (stereo)
Eleven stems. Add a percussion overdub and an acoustic guitar for the slow song and you top out around 13 or 14. Notice what is missing: the second amp mics and DI files got merged away, and the harmony takes live inside the backing-vocal stem. Every line is a role, which means every line is a fader that does something musical.
Whatever your count, three mechanical rules make it work. Every stem starts at bar one, even if the instrument is silent until the second chorus, and runs the same length so the files line back up on upload. Name each file by its role, Kick.wav and Lead Vocal.wav, never Audio1.02.
Export dry and lossless: WAV or FLAC, no limiter on the master bus, no clipping anywhere. Reverbs and heavy compression are usually better left off, since a printed effect cannot be removed later (keep one only if it defines the part). And if the recording underneath is the weak link, How to Record a Band Rehearsal That's Actually Mixable covers that for next time.
Where the 16 and 24 stem limits fit a real band
Bandmixr takes up to 16 stems per project on the free plan and 24 on the Creator and Pro plans. The five-piece with a split kit uses eleven slots, which leaves free-plan room for percussion and a synth pad. The 24-stem ceiling covers a horn section and a stack of overdubs on top of that.