StemDeck

Overview

StemDeck is a free workspace for splitting songs into individual parts, inspecting their musical measurements, and exporting practice or remix material. It is best suited to musicians, teachers, producers, hobbyists, and listeners who want local, focused audio work rather than a full digital audio workstation. The combination of six-way separation, built-in controls, and self-hosting makes it unusually flexible for a no-cost tool, while throughput remains tied to the computer running it.

Key features

StemDeck uses the Demucs htdemucs_6s model to create vocals, drums, bass, guitar, piano, and other-sound stems. Six distinct parts are useful for learning a line, checking an arrangement, preparing a backing track, or experimenting with a remix. The practical limitation is that the server handles one job at a time, so a large collection must be processed sequentially and speed depends on local hardware.

It accepts MP3, WAV, FLAC, OGG/Opus, MP4, and M4A files, as well as YouTube URLs. Uploads can reach 400 MB and tracks can run for 60 minutes. Batch processing is supported, but the single active-job limit means batching improves organization rather than delivering concurrent throughput.

Waveform lanes provide mute, solo, volume, and looping controls. Individual stems or a custom mix can be exported as WAV or MP3. This covers rehearsal, transcription, teaching examples, and quick arrangement sketches; users seeking extensive multitrack editing or production features will still need a dedicated DAW.

Analysis includes BPM, key, scale, confidence, integrated LUFS, and sample peak level. These figures give a useful starting point for practice plans, level matching, and remix decisions, while the confidence value helps indicate when a detected key or scale deserves verification.

Processing runs locally: StemDeck says audio is neither transmitted nor retained, cached, or redistributed by the app. Internet access is required for YouTube downloads and for the initial model download of about 170 MB; the model is then cached. That is a meaningful privacy advantage for unreleased or sensitive recordings, with the trade-off that your machine must supply the processing resources.

The project documents Docker and Unraid deployment and running its web server from source. Its local REST API supports jobs, status checks, cancellation, stem streaming, video export, and server-sent job events, making it suitable for a controlled home server or an automation workflow as well as the desktop interface.

Pricing

StemDeck — free, forever. The free plan requires no account, subscription, quota, or upload allowance beyond the stated 400 MB file limit and 60-minute track limit. It includes batch processing, WAV and MP3 export, a desktop app, and API access. There is no free trial because the product is free permanently. One job at a time is the principal operational constraint, so this plan fits individual practice, teaching, and occasional remix work better than teams processing libraries in parallel.

Platforms

StemDeck is available through its API and web interface, with desktop support on Linux, macOS, and Windows. It can also be self-hosted, including documented Docker and Unraid setups. There is no mobile app, so phone-first workflows are not a match.

Who it's for

Choose StemDeck for private song practice, transcription, classroom demonstrations, home remixing, or local analysis when avoiding uploads matters. Self-hosting and the API also suit technically inclined users who want control over deployment or automation. Look elsewhere if you need mobile apps, cloud-scale parallel processing, or a broader production environment than its focused mixer and exporter provide.

Pros and cons

• Pros: Six useful stem categories cover common learning and remix tasks.
• Pros: Local processing and self-hosting keep audio under your control.
• Pros: Imports include common audio/video files and YouTube URLs, with 400 MB and 60-minute limits.
• Pros: Waveform controls, analysis metrics, exports, and REST endpoints form a coherent workflow.
• Cons: Only one job runs at a time, limiting high-volume work.
• Cons: Processing performance varies with your hardware.
• Cons: No mobile app and no indication of a full production-suite feature set.

Alternatives

Stem Separation Software is the broader category guide for comparing more tools.

Pick AudioShake instead if you want Android or iOS access, a free trial, or a starter allowance of 200 credits with MP3 export and files up to 10 minutes.

LALAL.AI is a freemium cross-platform option with a free relaxed queue, 200 MB files, and preview results.

Choose Moises for mobile apps and a free tier capped at five uploads per month and five-minute files.

Pymss is another free, open-source, local-running alternative.

Fadr fits users wanting MIDI detection and a Remix Maker, with a free basic tier and a $10 monthly Plus plan.

MVSEP suits users who prefer many AI models and a web service, though its unregistered tier limits files to 10 minutes and 100 MB.

Audiola is a free desktop app for Windows, macOS, and Linux.

Open-Unmix is a free, MIT-licensed self-hostable option.

Verdict

StemDeck is a strong choice for anyone who wants private, no-cost stem separation with analysis, basic editing, exports, and an API in one self-hostable package. Choose it for focused practice or remix work on a capable computer; look elsewhere for mobile use or sustained parallel processing.