Show HN: Audiomass – a free, open-source multitrack audio editor for the web

Original Article ↗ Hacker News Discussion ↗

A new browser-based audio editor, Audiomass, is drawing praise for offering multitrack editing, FLAC support, offline/PWA mode, and a surprisingly smooth UX in under 100KB of JavaScript. Commenters compare it favorably to tools like Audacity and Cool Edit Pro for quick editing, podcast work, and simple multitrack mixes, while noting its current lack of MIDI/VST support and some limitations with very large files and autosaving. The creator emphasizes a privacy‑respecting, no‑backend design and “constrained creativity” around file size, and there is active interest in potential future features such as additional formats, plugin-style extensibility, and better collaboration workflows.

Overall reception

  • Strongly positive reactions; many find it smooth, intuitive, and reminiscent of Cool Edit Pro / early Logic.
  • Several users say they’ll use it instead of heavier desktop tools for simple edits and quick tasks.
  • Some UX confusion exists (e.g., getting “stuck” in the single-editor view, unclear controls like “waveform box”).

Features and UX

  • Multitrack: unlimited channels; waveform “boxes” can be moved between tracks and double‑clicked for detailed editing.
  • Keyboard and selection model: selections drive where effects apply; some want clearer previews and real‑time track‑based effects rather than clip‑based, offline processing.
  • Hidden/advanced features: markers, zero‑crossing selection, tempo tools, frequency analyzer, mixer, crossfades, presets, and detachable windows are praised but not very discoverable.
  • Requests: easier fade timing controls, silence detection/labeling (like Audacity), better tooltips, optional light mode.

Performance, file size, and limits

  • Frontend-only, canvas- and DOM-based rendering; currently no WebGPU.
  • Works well for typical podcast-length files (10–120 min); one user loaded a 12‑hour book successfully but saw zoom/waveform scaling issues.
  • Developer notes that very long files and some heavy operations can be slow; pyramid caches help but have edge cases.

Formats, MIDI/VST, and stems

  • Handles FLAC out of the box; MP3/WAV export plus FLAC codec added recently.
  • Some formats like XM modules are currently unsupported; possible but constrained by bundle-size goals (~100KB JS).
  • No MIDI or VST support at present; several users would like this.
  • Requests for importing “stem bundles” from AI tools and stem splitters.

Architecture, privacy, and offline use

  • No backend: after initial load, no further network requests; emphasize privacy, no uploads, no ads.
  • IndexedDB caching exists but is considered unreliable, so there’s no aggressive autosave yet.
  • PWA/offline mode is highlighted as a major benefit.

Licensing and “open source” status

  • Project is described as free and open, but the site initially lacked a formal license.
  • Discussion notes this has been raised for years; the developer informally says “do whatever you want” (closest to MIT/CC0), but others urge choosing a standard OSS license.

Comparisons and collaboration ideas

  • Compared to Audacity, Ardour, Ocenaudio, Bandlab, OpenDAW, and web DAWs; consensus is that this is an audio editor, not a full DAW.
  • Separate thread explores “GitHub for music” / cloud collaboration; existing tools (Bandlab, Ninjam, others) are cited but seen as imperfect.