Three tabs, three different questions, and a fourth shape hidden inside the first. What each mode is for, and what a paid plan actually unlocks — which is not what most people assume.
Lesson 2 · core · 8 min read
Open Stem SplitterThe picker has three tabs, and choosing between them is the single decision that decides how much work a job takes. They are not three settings on one operation. They are three different questions, and picking the wrong one usually means doing by hand something the tool would have done in one step.
The three tabs, in the order the picker shows them.
The useful test is not “what do I want to remove” — it is “what do I want to end up holding”. A set of parts is Split. One named instrument, on its own, is Isolate. The song minus something, still mixed, is Exclude.
A backing track to sing over
The bass line to learn by ear
A rough multitrack to remix from
A drum kit broken into kick and snare
Tip
Exclude is the mode people find last and use most. Anything phrased as “the song without the ___” — a karaoke track, a practice track for your own instrument, a bed with the vocal gone — is one click here and a small project anywhere else.
Isolate and Exclude both read from one instrument catalogue, grouped into families: vocals, guitars, bass, keys, strings, brass, woodwinds, folk & world, drums & percussion and production. 45 is the size of the menu, not the size of the output — you pick from 45 instruments, and any one job returns at most 16 files.
A search box sits above the grid on both tabs, and it is the fastest way in — a catalogue this size is quicker to search than to scroll. Exclude shows a shorter grid than Isolate on purpose: only 8 instruments can be removed from a mix (Vocals, Drums, Bass, Guitar, Piano, Other, Saxophone and Wind), and the tab offers only those rather than listing options that would fail.
Careful
Picking more instruments does not make a job better. A single job returns at most 16 files, and — more to the point — an instrument that is not in the recording still comes back as a file. It is just a file with something else in it. Lesson three is about that failure specifically.
Below the 3 preset cards, under a small heading reading “Detailed decomposition”, sit three more options. They are worth scrolling for: they produce parts nothing else in the tool can, because they break a single instrument into its pieces rather than separating one instrument from another.
The decomposition packages. Every count is a ceiling, not a promise.
Note
“Up to” is doing real work in that table. A decomposition only yields the parts the recording contains — a track with no cymbals produces no cymbal file — so the count is the most you could get, and a quiet arrangement will get fewer. Treat it as a ceiling every time.
This is where most people's model of the tool is wrong. The gate is not one line with free on one side and paid on the other. There are three of them, on three different things, and the one everybody assumes is gated — how many parts you get — is not.
Three independent axes. Only the middle two are gated at all.
Read the first row again, because it is the one that surprises people: All 3 presets — up to 6 parts — cost nothing beyond the credits the job meters. Nothing about the number of parts is gated here. A free account can take any song apart into 2, 4 and 6 parts as often as its credits allow. What a plan buys you is the ability to name instruments, and the ability to decompose one.
The credit rate does not change with your plan either. Every public tier meters stem splitting at the same 660 credits per minute and differs only in how many credits it includes each month; Enterprise is the only tier with custom terms. There is no unlimited stem plan and there has not been one since the ladder was set.
Instruments your plan does not cover stay in the grid. They are greyed out, they carry the name of the plan that unlocks them, and each group shows one upgrade bar above its locked cards rather than a padlock on every tile. Some instruments — vocals, guitar, drums and backing track — are open to everyone.
That is a deliberate choice and worth understanding as a reader: you can browse the whole catalogue, search it, and find out whether the instrument you need exists at all before deciding whether it is worth paying for. A tool that hid its locked options would make “does this even do saxophones?” a question you can only answer by subscribing.
Questions
Free to start
Reading about a style description only gets you so far. The studio is free to use — write one sentence and hear what comes back.
1,000 credits every month. No card required.