Audacity 4.0: A New Era of Audio Editing

Overview: Audacity 4.0 represents a massive overhaul of the software. The application interface has been completely reconstructed using the Qt framework, bringing a host of quality-of-life enhancements and a fundamental shift in how clips are handled.

While the majority of workflows from version 3 are still intact, users will notice that certain controls have been relocated or modified to fit the new architecture.

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✂️ The New Clip-Editing Model

The most significant change is the introduction of a clip-based workflow. Instead of treating audio as a continuous stream, you can now interact with clips directly.

Interaction Logic

Key Clip Behaviors:

• Grouping: When you copy, paste, duplicate, or move grouped clips, they remain synchronized.
• Overlapping: Moving one clip over another now replaces the overlapping section rather than blocking the movement.
• Dynamic Tracks: Audacity now automatically generates tracks as needed, adapts to compatible channel layouts, and supports pasting audio directly from the OS clipboard.
• Precision: New alignment guides, sample-boundary snapping, and customizable per-project snap settings ensure pinpoint accuracy.

Available Split Commands:

• Split
• Split-cut
• Split-delete
• Split at silences
• Split to a new track

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🎨 Interface and Tooling

The transition to Qt enables native high-DPI rendering, ensuring the app looks sharp on all monitors.

Customization Options

Notable UI Changes:

1. Home Screen: A new landing page displays recent projects complete with preview thumbnails.
2. Contextual Tools: The old dedicated modes (Select, Envelope, Draw, Multi-tool) are gone. Now, functions appear based on context:
   • Clip Gain Mode $\rightarrow$ Volume envelopes appear.
   • Deep Zoom $\rightarrow$ Sample drawing becomes active when zoomed to individual samples.
3. Refined Controls: Parameters for effects and tracks now use consistent rotary knobs. Double-click to reset; use the fine-adjustment modifier for precision.
4. Timing Preservation: Cut, copy, and paste now offer explicit choices: leave a gap or shift subsequent material to maintain timing.

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🎙️ Playback and Recording

The recording and playback engine has been modernized to match the new UI.

• Navigation: The playhead is always visible and can be dragged manually to any position.
• Flexible Recording: You can now initiate recording at any point on the timeline, which automatically generates a clip at that location.
• Revised Logic: Loop boundaries and the relationship between selections and playback have been overhauled.
• Rebuilt Features: The following have been rewritten for the new interface:
  • Punch and Roll
  • Lead-in recording
  • Latency compensation
  • Software playthrough & per-track input monitoring.

Audio Configuration

The Audio Setup menu is now more robust, featuring:

• System-default device integration.
• Refreshable device lists.
• Customizable channel mapping.
• Automatic detection of OS-level device changes.
• Windows Exclusive: Official builds now support ASIO for both playback and recording.

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🎚️ Tracks, Effects, and Analysis

• Visual Feedback: Track headers now feature integrated, live meters for playback and recording.
• Effect Consistency: Preset management is now uniform across realtime, destructive, and built-in effects.
• Plugin Support:
  • VST3, Nyquist, LV2 (Linux), and Audio Units (macOS).
  • If a plugin lacks its own GUI, Audacity can generate generic controls.
• Spectrogram: Now features faster rendering and improved rulers/guides.

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📁 Project Management and Files

Audacity 4 introduces a new project file extension: .aup4.

$\text{Project Versioning: } .aup3 \rightarrow .aup4$

• Migration: .aup3 files will open and convert to .aup4 automatically without altering the original source file.
• Data Storage: The new format stores appearance data and preview thumbnails.
• Branding: The developers also took the opportunity to update the Audacity logo.

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⚠️ Compatibility and Known Issues

Not everything from version 3 made the jump to 4.0. The team is working to bring these back in future updates:

• Time Tracks
• Note/MIDI tracks
• Mixer
• Macro Manager & Scripting Pipe
• VAMP and LADSPA plugin hosting

Note: Sync-Lock, Play-at-speed, and old tool modes were not removed but replaced by the new workflows mentioned above.

Additionally, some specific effects, analyzers, and rendering/exporting features are currently missing.

Update Note: The source package audacity-sources-4.0.0.tar.xz has been revised to include the following third-party libraries:

- SoundTouch
- sbsms