Splitter.ai gives you stems and stops there. SignalKey gives you 2-stem in your browser (free, instant, no upload), 4-stem on Studio cloud GPU, plus BPM, key, Camelot, chord chart, MIDI export and LUFS check — all in one upload.
No spin — what each tool actually does and where the lines are drawn.
Stem separation as part of a full music analysis pipeline. Free runs vocal/instrumental split in your browser (zero upload, zero cost). Studio at $19/mo runs cloud Demucs for true 4-stem separation, alongside BPM, key, chords and MIDI in the same pass. Tool pages stay ad-free.
Specialist stem separation service. Fast turnaround on the core 2-stem and 5-stem splits. Free tier with ads, paid plans for higher quality and more stems.
Free tiers both work; SignalKey's costs us $0 because it runs in-browser, where Splitter.ai funds its free tier through track / quality caps.
What each tool does, what it doesn't, and where the gaps are honest.
| Feature | SignalKey | Splitter.ai |
|---|---|---|
| 4-stem split (vocals/drums/bass/music)Studio plan only on SignalKey (cloud GPU). | ||
| 5-stem split (adds piano / guitar) | ||
| 2-stem split (vocal / instrumental) | ||
| 24-bit WAVStudio-only on SignalKey. | ||
| No watermark on free tier |
| Feature | SignalKey | Splitter.ai |
|---|---|---|
| BPM detection | ||
| Key + Camelot | ||
| Audio → MIDI | ||
| Chord detection | ||
| LUFS metering |
| Feature | SignalKey | Splitter.ai |
|---|---|---|
| Browser-based | ||
| Batch upload | ||
| API access | ||
| Live mic tools (tuner, metronome) |
Both tools are good. The right answer depends on what you're actually doing.
Not yet. 4-stem (vocals / drums / bass / music) is the standard split. 6-stem isolation is on the roadmap as a Studio feature. If 5+ stems is critical now, Splitter.ai is the better choice.
Methodology: Researched April 2026 against the public Splitter.ai product page. Free tier limits and paid pricing pulled at time of writing. If anything in this comparison reads as inaccurate, please email hello@signalkey.io and we'll update.
Drop a song and see the analysis pass — BPM, key, Camelot, stems, MIDI, LUFS — in one go. Free forever.