StemDeck review (2026): an honest verdict on the free, local, open-source AI stem separator — separation quality, privacy, and the real limits for creators.
StemDeck is one of the easiest free stem separators to recommend for what it actually is: a local, open-source desktop app that runs Meta's Demucs on your own machine, splits a song into up to six stems, and hands you a real multitrack mixer to solo, mute, and export — no account, no upload, no subscription. For musicians who practice, transcribe, remix, or build karaoke tracks, and for anyone who won't send unreleased audio to a cloud server, it's excellent value at exactly $0. The honest limits are hardware-bound speed on CPU-only machines, some setup friction, no mobile app, and separation quality capped by open-source Demucs rather than a proprietary model. Worth it: yes, for its narrow, well-executed job.
StemDeck is a free, open-source stem-separation app that runs entirely on your own computer. Built by an independent developer (Thales Claro) and released under the Apache 2.0 license, it drew a round of coverage across producer and music-tech press in August 2026 as a no-account, no-upload alternative to cloud splitters like Moises and LALAL.AI. You drop in an audio file — or paste a YouTube URL — and StemDeck uses Demucs (Meta's open-source separation model) to pull the track apart into vocals, drums, bass, guitar, piano, and other, then opens a browser-based multitrack mixer where you can solo, mute, loop, zoom, and export.
This review scores StemDeck for what it is — a focused, local audio utility — not against content engines or publishers, which it does not claim to be. The dimensions below rate the things that decide whether a musician or producer should install it: how clean the separation is, how well the local/private model works, how broad the format support is, how usable the built-in mixer is, how much setup and hardware it demands, and whether the free, open-source price is the bargain it looks like.
Two things frame the verdict. First, StemDeck is a front-end for open-source models — its separation ceiling is set by Demucs (specifically the six-stem `htdemucs_6s` model), plus an optional UVR karaoke model for lead/backing vocal splits, so its own value-add is the local pipeline, the mixer, and the zero-cost, zero-upload access, not a new frontier separator. Second, because it runs on your hardware, your experience depends heavily on whether you have a supported GPU (NVIDIA CUDA or Apple Silicon) or fall back to CPU — a distinction that changes processing from fast to slow.
StemDeck is a desktop stem separator that does its work locally. Instead of uploading a song to a web service, you run the app on Windows, macOS, or Linux and the model executes on your own machine, automatically choosing the best available compute — NVIDIA CUDA, Apple Silicon MPS, or a CPU fallback. It accepts MP3, WAV, FLAC, OGG/Opus, MP4, and M4A files, and can also pull audio from a YouTube URL for material you have the rights to use. Separation is powered by Demucs `htdemucs_6s`, which splits into up to six stems (vocals, drums, bass, guitar, piano, and other); an optional UVR-MDX-NET karaoke model adds a lead-versus-backing vocal split. Once a track is processed, StemDeck opens a DAW-style waveform mixer with per-stem faders, mute/solo, VU meters, looping, and export of individual stems or a custom mix (rendered via FFmpeg). It also runs light analysis — BPM detection, key/scale, and LUFS loudness. It's free and open source under Apache 2.0, with the explicit pitch: no account, no upload, no subscription — audio never leaves your machine. What StemDeck is not is a content engine or a publisher. It separates audio and lets you remix and export it; it does not caption a clip, generate video, build social posts or carousels, write anything, keep a brand voice, or post to any platform. That's not a shortcoming so much as a scope: it's a single-purpose audio tool that does its one job well.
StemDeck fits musicians, producers, students, and hobbyists who need clean stems for practice, transcription, remixing, mashups, karaoke, or sampling — and who would rather not pay a monthly subscription or upload their audio to someone else's server. It's a particularly strong fit for anyone working with unreleased or licensed material where privacy matters, and for people comfortable installing a desktop app or running a local server. It's a weaker fit for users who want a zero-setup web tool they can open on any device, mobile users (there's no phone app), and anyone on a CPU-only machine who needs fast turnaround, since local processing without a supported GPU is slow. And if your goal is turning a remix or cover into published content, StemDeck is the audio step, not the content workflow — that's a different category of tool.
| Dimension | Score | Why |
|---|---|---|
| Separation quality | 4.3 / 5 | Demucs htdemucs_6s gives clean six-stem separation; strong for a free model, though proprietary services can edge it on some material. |
| Local processing & privacy | 4.9 / 5 | Everything runs on your machine — no account, no upload, no subscription. Best-in-class for privacy-sensitive audio. |
| Format & input support | 4.4 / 5 | Accepts MP3, WAV, FLAC, OGG/Opus, MP4, and M4A, plus YouTube URLs for material you have rights to. |
| Built-in mixer & editor | 4.2 / 5 | A real DAW-style waveform mixer with per-stem faders, mute/solo, VU meters, looping, and custom-mix export. |
| Setup & ease of install | 3.5 / 5 | Native Windows/macOS builds are straightforward; Linux runs via web server or Docker, and local ML setup adds friction for non-technical users. |
| Cross-platform support | 4.3 / 5 | Windows (CPU and CUDA), macOS (Apple Silicon MPS and Intel CPU), and Linux via web/Docker — but no mobile app. |
| Performance & speed | 3.7 / 5 | Fast on a supported GPU (CUDA/MPS); CPU-only fallback works but is noticeably slow on longer tracks. |
| Music-analysis extras | 4.0 / 5 | Handy built-in BPM, key/scale, and LUFS readouts alongside separation. |
| Price & value | 5.0 / 5 | Free and open source under Apache 2.0 — no cost, no quota, and no upload, versus paid cloud subscriptions. |
On price, StemDeck is as favorable as it gets: it's free and open source under the Apache 2.0 license, with no account, no per-track quota, and no upload. Set against Moises and LALAL.AI — which gate higher stem counts, longer tracks, and batch processing behind monthly subscriptions or credit packs — a capable six-stem local separator at $0 is a genuine bargain for anyone who separates audio regularly.
The honest caveat is that "free" isn't costless. StemDeck spends your hardware instead of your money: on a machine without a supported GPU, processing is slow, and you take on the setup — installing the app (or running the Docker/web-server path on Linux) and letting a local model do the heavy lifting. Cloud tools trade a subscription for zero setup, instant availability on any device, and someone else's GPUs. For privacy-sensitive or high-volume work the local model wins clearly; for a one-off separation on a phone, a web tool is simpler.
The comparison only misleads in cross-category framing. StemDeck (a free local audio utility) and a content engine like Kompozy at $99/month are not competing line items — one isolates stems on your machine, the other turns a source into finished, on-brand video and posts and publishes them across platforms. If you're deciding how to separate audio privately for free, StemDeck is the value pick. Turning that audio into published content is a separate budget for a separate tool.
| Use case | Fit | Why |
|---|---|---|
| Practice, transcription, and learning parts by ear | Strong | Soloing and muting individual stems in the built-in mixer is exactly what StemDeck is built for. |
| Remixing, mashups, and sampling | Strong | Six clean stems plus custom-mix export give producers real raw material to work with. |
| Karaoke / instrumental (vocal removal) | Strong | Demucs plus the optional UVR karaoke model isolate or remove vocals, including a lead/backing split. |
| Privacy-sensitive or unreleased audio | Strong | Nothing uploads — the model runs locally, so licensed or unreleased material never leaves your machine. |
| Zero-setup one-off separation on any device | Weak | It's a desktop/local app; a browser tool is simpler if you just want a single quick split with no install. |
| Fast turnaround on a CPU-only laptop | Weak | Without CUDA or Apple Silicon acceleration, local processing of longer tracks is slow. |
| Turning a remix or cover into published content | Weak | StemDeck exports audio; it doesn't make video, posts, or publish — that's a content engine's job. |
To be clear and honest: Kompozy is not a competitor to StemDeck, and it is not a stem separator. If your need is splitting a song into stems privately and for free, StemDeck is a genuinely good fit and Kompozy doesn't replace that step — nor does any content tool.
Where Kompozy matters is the step after the export. StemDeck ends at a set of WAV files: an instrumental, a vocal, a custom mix. For a musician or audio creator, that file is raw material for the thing an audience actually sees — a remix breakdown, a cover, a "how I made this" post, a Reel with your instrumental under it. Turning that into finished, on-brand content is a different job, and it's Kompozy's. Bring Kompozy the instrumental you pulled in StemDeck and it becomes the music bed under a Listicle Video or a Marketing Short; feed it the isolated vocal or the story behind the track and it generates the surrounding set — Persona Shorts and HeyGen avatar video with a consistent persona, HyperFrames carousels, quote graphics, a blog, and a newsletter — all governed by one Persona Brief, then captioned, reframed to 9:16, 1:1, and 16:9, and published across the eight social platforms plus blog and email. The honest framing is a division of labor: let StemDeck separate the audio, and run a content engine to turn what you make from it into content people actually see.
Yes. StemDeck is free and open source under the Apache 2.0 license, with no account, no per-track quota, and no subscription. Because it runs locally, the trade-off for "free" is that processing uses your own hardware and is faster with a supported GPU (NVIDIA CUDA or Apple Silicon) than on a CPU-only machine.
Privacy is its main selling point. Everything runs locally on your own computer and audio never uploads to a server — the project explicitly advertises "no account, no upload, no subscription." That makes it a strong choice for unreleased or licensed material you don't want leaving your machine. It's open source, so the code is public and auditable.
StemDeck uses Demucs, Meta's open-source separation model — specifically the six-stem `htdemucs_6s` model — to split tracks into vocals, drums, bass, guitar, piano, and other. For a lead-versus-backing vocal split it can use a UVR-MDX-NET karaoke model. It's a front-end and pipeline around these open-source models, not a proprietary separator.
Up to six: vocals, drums, bass, guitar, piano, and "other." It can also produce a lead/backing vocal split via the optional karaoke model, and the built-in mixer lets you solo, mute, balance, and export individual stems or a custom mix.
StemDeck runs locally and is free and open source; Moises and LALAL.AI are cloud services that upload your audio and charge via subscriptions or credits. The cloud tools offer zero setup, mobile apps, and their own GPUs, and can edge StemDeck on quality for some tracks. StemDeck wins on privacy, cost, and no quotas — but you supply the hardware and some setup.
Yes. There are native builds for Windows (CPU-only and NVIDIA CUDA) and macOS (Apple Silicon with MPS acceleration, and Intel CPU), and Linux runs via a web server or Docker. It auto-detects the best available compute device. There is no mobile app.
No — that's outside its scope. StemDeck separates and exports audio; it doesn't make video, captions, or posts, or publish anywhere. To turn an instrumental, an isolated vocal, or a remix into captioned, on-brand video and posts across platforms, pair it with a content engine like Kompozy, which handles the video, format fan-out, and publishing.