Separate
Demucs splits vocals, drums, bass, and guitars into stems. Today it runs on a PC, not on a phone.
Studio + Pocket · 2026 proposal
From a separated song to the sound you play over it.
Studio creates the package. Pocket brings it to your phone and works without a PC.
No account. No cloud. Your audio never leaves your computer.
A minor
92 BPM 4/4 8 barsAm2×
×
○
○
A · C · E
F2×
○
○
F · A · C
C2×
×
○
○
C · E · G
G2×
○
○
○
G · B · D
8 bars/
AmFCG
AmFCG
A/B loopofflinesynthetic data
Product view · synthetic data, no audio
<1%
BPM error against the reference
measured · 2 songs
69/69
voicings validated by script
0 errors · repo
1.43 GB
peak RAM on PC with 6 stems
measured · 30 s · Oct 15
0
external dependencies in the lightweight engine
stdlib + repo modules
The problem
Four tools for a single practice session.
Separate the song, extract chords and tempo, build the loop, and find the sound. Today that means four programs, four files, and a browser tab. The idea is to make it one flow.
Analyze
Chords, BPM, and key with a measurable reference: not “about right,” but with error and date.
Loop
Eight bars, A/B loop, and a fretboard that shows what to play. No fighting the mouse.
Sound
The step no app solves on its own: tone. This is where the rig connects; no magic is promised.
The flow
Four steps. A PC to create, a phone to practice.
The phone does not need the PC to play. The PC is only needed when there is a new song to separate and analyze.
You import
Choose the audio in Studio. Nothing is uploaded to any server.
Studio separates and analyzes
Demucs, chords, tempo, and key. The report builds itself.
You export .st2t
A package with stems, JSON, and SVG. Verifiable, no cloud.
Practice with Pocket
Airplane mode, A/B loop, fretboard, and bar strip. No PC, no account.
Two apps, one package
Studio on the computer. Pocket in your pocket.
They are not two separate products: they are two moments in the same flow. The contract is the same
file: .st2t.
Studio
desktop · create
- Separates stems with Demucs and analyzes chords, BPM, and key.
- Native window: no
localhost, no port, no browser tab. - Exports a verified package with checksums.
- Works with the audio on your disk. Nothing goes to the cloud.
Android · practice
- Imports the
.st2tand practices in airplane mode. - A/B loop, stems, fretboard, and bar strip.
- Lite is the MVP: it does not analyze on the phone.
- Pro is future work and is enabled by benchmark, not by brand.
The product view
The report that already exists, without third-party audio.
The demo uses synthetic data and the same visual language as the real reports. It is not a screenshot: it is a working mockup you can open.
A minor
92 BPM 4/4 8 bars minor pentatonicAmi
×
○
○
A · C · E
FVI
F · A · C
CIII
×
○
○
C · E · G
GVII
○
○
○
G · B · D
Ami→
FVI→
CIII→
GVII
Synthetic demo. Contains no audio or third-party works.
Open interactive demo →
Measurements, not promises
What has been measured and what is still a target.
Each row says how and when it was measured. “Measured on PC” is not the same as “mobile target”: the site does not mix the two columns.
| What | Value | How it was measured | Status |
|---|---|---|---|
| BPM error | <1% | Against the public reference, 2 songsPENDIENTES.md · 14/Oct | measured |
| Voicings | 69/69 | validar_digitaciones.py, 0 errorsPENDIENTES.md · 14/Oct |
measured |
| Separation RAM | 1.43 GB peak | 30 s clip, 6 stems, FP32, sampled every 2 sPENDIENTES.md · 15/Oct | measured on PC |
| Separation speed | 234 s in 103 s | Boogie with Stu, 6 stems, 2.27× real timeoutput/logs |
measured on PC |
| Pocket Lite offline | airplane mode | Import, view, loop, and play without a PCD3 cutoff criterion | target |
| Pocket Pro on-device | go/no-go | 30 s benchmark: time, peak RAM, thermals, and batteryDISTRIBUCION.md §7.1 | to be measured |
Project status
What is done, what is in progress, and what may end in “no.”
The order follows DISTRIBUCION.md. The website (W0-W4) runs in parallel and blocks
neither Studio nor Pocket.
Decision
Studio + Pocket, UI stack, and .st2t contract.
Export
A valid .st2t from the 2 songs, with checksums.
Studio MVP
Native window, report, export. Zero terminal, zero browser.
Pocket Lite
Import, play, loop, and fretboard in airplane mode.
Distribution
Signed installer, offline license, encrypted assets.
Pairing
Optional: view a new song without exporting, LAN + token.
Pocket Pro
Analyze/separate on the phone. Only if the §7.1 benchmark passes.
Web
Bilingual landing, synthetic demo, and status. Deploy preview and domain.
Frequently asked questions
What to know before you try it.
If something is not here, it is in the repo docs. The site does not invent an answer to cover a gap.
Do I need the PC to practice?
No. Once the .st2t is exported, Pocket works in airplane mode. The PC is only
needed to create the analysis for a new song.
Does my audio get uploaded anywhere?
No. Everything is local; the site has no backend, and the app does not send audio. The demo uses synthetic data, and the metronome is generated in the browser.
Will Pocket Pro work on my phone?
It is decided by a 30 s benchmark on that device. If it does not pass, it stays on Lite. There is no promise by brand or tier.
When can I download it?
When D2/D3 are done and the installer is signed. The site publishes the status; there is no fake download button.
What about Chordino and the GPL?
It is a legal blocker under review. The possible paths are to separate it as a GPL process, replace it with a permissive model, or publish that part under the GPL. Nothing is sold until it is resolved.
How much will it cost?
It is decided in the business plan. The site does not invent prices: it publishes the edition and the status.
Try it with synthetic data. No account.
The demo opens in the browser, shows the report, and plays a metronome. It asks for no email and uploads nothing.