A practice studio that splits a song into six stems, and what I measured

说明与用途

Stemwise 是一款浏览器工具，可将音轨拆分为六个声轨，检测节拍和和弦，并支持循环、时间拉伸、转调和导出声轨与 MIDI。

问题

Musicians need a quick way to isolate stems, loop sections, and analyze chords without complex software.

结果

Stemwise processes a 2‑minute song in 1 s on an RTX 5090 (122.5× realtime) and 45.2 s on a Ryzen 5 7500F (2.7× realtime). Chord root accuracy is 0.739 on strummed guitar and 0.265 on solos; beat detection is reliable on strummed parts.

工作流

• Drop an audio file onto the local web page
• Stemwise runs Demucs htdemucs_6s to separate into six stems
• Beat_this detects beats and downbeats
• CQT chroma model estimates chords and key
• User interacts with the player: mute/solo stems, loop bars, slow tempo with pitch held, transpose, play along to click
• Export menu generates backing track, stems, chord sheet, and MIDI beat grid

证据

Drop an audio file on a local page. Stemwise separates it into vocals, drums, bass, guitar, piano and other with Demucs htdemucs_6s

来源

The browser engine is an AudioWorklet that does WSOLA time stretching, with a cubic resampler for transposing.

来源

stemwise bench runs the separation on a 2 minute 3 second song. On an RTX 5090 it takes 1.00 s, which is 122.5x realtime, best of 3 after one warmup run in fp32.

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The chords come from a CQT chroma model with templates, a bass bias and Viterbi smoothing.

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Only one song is processed at a time.

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