Audacity 4.0 rebuilds on Qt, rethinks clips, and drops Sync-Lock

At 10:19 on 3 September 2026, the tag Audacity-4.0.0 showed up on the project’s GitHub repository. According to the release notes, this is an interface rebuilt on Qt, with a new model for editing clips. Those notes talk about the software and nothing else — not one line about how the project is being run — which leaves exactly one honest way to judge the release: look at what it does.

The interface got more than a fresh coat of paint

Moving to Qt brings native high-density rendering, so waveforms come out sharp on modern displays. Toolbars and panels move, detach and hide, and whatever arrangement you end up with can be saved as a Workspace; three ship in the box — Modern, Classic and Music. Add light, dark and high-contrast themes, accent colours, track colours and several clip styles. A start screen lists your recent projects with preview thumbnails, which sounds like nothing at all until you are staring at three files called final_v2.

The tools are gone, the gestures stay

This is the change that will trip you up in daily use: the Select, Envelope, Draw and Multi-tool modes no longer exist. Their jobs became contextual — volume envelopes show up in Clip gain mode, sample drawing appears once you zoom in to the sample level, and you split by holding S before you click. Sync-Lock goes out too, replaced by explicit variants of cut, delete and paste: either you leave a hole, or you shift everything that follows. Track and effect parameters now share the same knobs, with fine adjustment and double-click to reset.

The clip is now the thing you grab

You select a clip by clicking its header, several with Shift-click, and moving, trimming and time-stretching all apply to the whole batch. Clips can be grouped, and they stay together when you move, copy, paste or duplicate them. They travel between mono and stereo tracks, and dropping a clip on top of an existing one replaces the overlapping portion instead of refusing to budge. Pasting creates a track if it has to, adapts compatible channel configurations, and accepts audio files straight from the system clipboard. On the transport side, the playhead stays visible while you navigate, moves with the mouse, and playback can jump somewhere else without stopping. Recording starts anywhere on the timeline and creates a clip right there. Official Windows builds ship with ASIO support for both playback and recording.

What you leave behind

Projects use the .aup4 format. An .aup3 opens and converts without touching the original file, but the converted project can no longer be saved back to .aup3: the door only swings one way. Old .aup files remain importable. The supported plugin formats are VST3, Nyquist, LV2 on Linux and Audio Units on macOS, and Audacity can generate controls when a plugin brings no interface of its own. Track headers gained playback and recording meters, and the spectrogram has been redrawn with faster rendering. The notes point out that most Audacity 3 workflows are still available, that some commands have moved, and that a list of version 3 features has not made the trip.

The project also changed its logo, which it presents as an act of audacity. After a rewrite that relocates half of what its users’ fingers already knew, yes — the logo is obviously the part that took nerve.