Audacity 4.0: The Open-Source Audio Editor's Biggest Release in a Decade

Audacity 4.0 dropped yesterday and it's the kind of release that makes you want to start a podcast just to try it. 1,049 points on Hacker News, 234 comments — the open-source audio editor that practically invented the genre just shipped its biggest overhaul since the project started.

Here's what changed and why it matters for anyone who records, edits, or produces audio.

Qt rebuild — the invisible foundation

The headline change is the migration from wxWidgets to Qt for the entire interface. That's the kind of infrastructure rewrite users never see but immediately feel. Native high-DPI rendering means Audacity no longer looks blurry on Retina displays. Toolbars float, dock, hide, and rearrange. You can save layouts as Workspaces — Modern, Classic, and Music come pre-loaded.

Light, dark, and high-contrast themes ship out of the box with accent colors, track colors, and multiple clip styles. The Home screen shows recent projects with preview thumbnails. It's the kind of polish Audacity never had because the underlying toolkit couldn't support it.

Non-destructive editing finally arrives

The old Audacity model was destructive: cut a clip and the audio was gone. 4.0 introduces a proper clip-editing model where clips can be selected directly, moved freely between tracks, and grouped. Selected clips share edits — move, trim, or time-stretch one and they all respond. Clips can even replace each other rather than blocking placement.

Splitting gets a dedicated tool (hold S and click). Paste handles more cases automatically — it'll create a track when needed, adapt channel layouts, and accept audio files from the OS clipboard. Alignment guides and sample-boundary snapping make precise edits less painful.

The old tool modes (Select, Envelope, Draw, Multi-tool) are gone. Their functions went context-sensitive: volume envelopes show in Clip Gain mode, sample drawing appears when zoomed in far enough. Sync-Lock was replaced with explicit delete/cut variants that either leave a gap or close it.

Playback and recording improvements

The playhead stays visible during navigation and you can drag it to jump. No more stopping playback just to scroll. Recording starts at any timeline position and creates a clip there. Loop boundaries and selection interaction were redesigned. Punch and Roll recording, latency compensation, and per-track input monitoring were rebuilt for the new interface.

Audio Setup now shows system-default devices, refreshable device lists, and custom channel mapping. Audacity can follow OS device changes automatically. Official Windows builds include ASIO support — no more third-party wrappers for low-latency audio.

The .aup4 project format

Audacity 4 introduces the .aup4 format. Your old .aup3 projects open and convert without touching the originals. The catch: converted projects can't save back to .aup3. Older .aup projects can be imported too. Project files now store preview thumbnails and the additional clip and appearance data 4.0 needs.

What's missing (for now)

The team was upfront about things that didn't make 4.0:

• Time Tracks
• Note/MIDI tracks
• Mixer board
• Macro Manager and scripting pipe
• VAMP and LADSPA plugin hosting
• Play-at-speed

These are slated for future releases. If your workflow depends on macros or MIDI, 4.0 might not be ready for you yet — but the 3.x branch isn't going anywhere.

Plugin and effects overhaul

Built-in effects, generators, and analyzers were rebuilt for Qt. Supported formats are VST3, Nyquist, LV2 (Linux), and Audio Units (macOS). When a plugin doesn't ship its own interface, Audacity generates controls automatically. The spectrogram was redesigned with clearer guides, rulers, and faster rendering. Preset handling is now consistent across built-in, destructive, and realtime effects — a minor miracle of UI discipline.

What this means for the ecosystem

Audacity is one of those projects that's easy to take for granted because it's been around since 2000. It powers podcasts, radio production, field recording, and probably half the voiceover work on YouTube. A 25-year-old codebase getting a ground-up Qt rewrite, non-destructive editing, and modern UI tooling isn't just a release — it's a statement that the project is investing in the next decade, not maintaining the last one.

The 1,049 HN points tell you the community agrees. But the 234 comments tell you something else: people care enough to argue about timeline loops, plugin compatibility, and workspace layouts. That level of engagement is rare for a tool this mature.

If you haven't looked at Audacity in a while — maybe you switched to something shinier during the Muse Group acquisition drama — 4.0 is worth another look. The destructive-editing pain point that drove people to paid alternatives is gone. The UI no longer looks like a 90s science fair project. And it's still free.

Source: Audacity 4.0.0 Release — GitHub | Hacker News Discussion