AudioFast Support

Any common audio format macOS can decode: MP3, AAC / M4A, WAV, AIFF, FLAC, ALAC, CAF and more, and you can mix formats when joining files. You can also import video files (MP4, MOV and so on) to extract their audio track.

MP3 (128 / 192 / 256 / 320 kbps), AAC (M4A), WAV, FLAC, ALAC (M4A), AIFF and CAF. You can set the sample rate, channels and bit depth, or export just the selection. The estimated file size is shown before you export.

Drag the files into the window (or press ⌘O). They line up end to end automatically. Drag clips in the sidebar list to change their order.

Import the voice first. Move the playhead to where the music should start, then choose Tracks ▸ Import to New Track… (or click "Import to New Track" under the timeline). The music goes on a new track and plays together with the voice. You can have up to 8 tracks.

The M (mute) and S (solo) buttons and the slider at the left of each track control that track. The "…" menu renames, moves or deletes the track. Drag a clip to slide it along its track, or onto another track.

Drag on the waveform to select it, then press ⌫ to delete; everything after it moves up to close the gap. To keep the duration, press ⌘L to replace the selection with silence. Press ⌘Z to undo. With several tracks, edits apply to the current track; the Clip menu has split and delete commands for all tracks.

Put the playhead near the cut and press ⇧Space to play 2 seconds on either side. AudioFast adds a 3 ms fade at non-continuous cuts by default to avoid clicks; you can turn "Avoid Pops at Cuts" off under "Project" in the inspector.

Choose File ▸ Open Folder… (or drag a folder into the window). The sidebar switches to "Folder" and shows subfolders as a tree. Click a file to edit it; ⌥⌘↑ / ↓ jump to the previous / next file.

This is a quick single-file editor: split, delete, fades, effects and silence tools all work, but tracks are not layered and other audio is not joined in.

Yes, and only when you press ⌘S: the edited audio replaces the original file (you are asked to confirm the first time, and you can choose "Save As…" instead). ⇧⌘S saves a new file and leaves the original alone.

Please note that saving re-encodes the audio in its original format, so lossy formats such as MP3 and AAC lose a little quality, and tags and cover art in the original are not kept. Formats AudioFast cannot write back (OGG, Opus, multichannel and so on) can only be saved as WAV, FLAC, MP3 and similar.

Select a clip and open the effect you want under "Effects" in the inspector: equalizer (5 bands plus low-cut and high-cut), compressor, echo and reverb, one switch each. The "…" menu at the top right has whole-chain presets (Voice Boost, Podcast, Telephone, Bass Boost, Hall Reverb, Echo) that you can fine-tune afterwards.

Choose Clip ▸ Process Silence… (⌥⌘S). The silent parts are marked on the timeline as you adjust the settings. "Remove Silence" deletes them, "Split at Silence" only cuts them apart, and "Trim Silence at Ends" only handles the start and end. If something is misdetected, adjust the threshold, the minimum length and the padding; if there is a lot of background noise, click "Auto" to estimate the threshold from the noise floor. With a selection, only the selection is processed.

Choose File ▸ Batch Process…, drag in several audio files (or folders), pick a format, tick "Remove Silence" if you want, choose an output folder and click "Start Processing". The original files are never changed.

Yes. ⌘S saves your edit as an AudioFast project (.audiofast, shown as a single file in Finder); open it later with File ▸ Open Project…. A project only records where your audio files are and does not copy your original audio. If you later move or rename a file, you can relink it when you open the project. You are warned about unsaved changes before quitting.

Yes. While there are unsaved changes, AudioFast periodically writes a recovery copy into its own folder, and offers to restore it the next time it starts. The recovery copy is removed automatically after you save or quit normally.

AudioFast runs in the macOS sandbox and can only access files and folders you explicitly give it through an open panel, drag and drop, or a save panel. That protects your privacy: it never scans your disk.

English and Simplified Chinese, following your system language. To change it, use System Settings ▸ General ▸ Language & Region, or set a language for AudioFast alone under "Applications" there.

The full list is under Help ▸ Keyboard Shortcuts. The most common: Space play / pause, S split at the playhead, ⌫ delete the selection, ⇧Space preview around the playhead, ⌘Z undo, ⌘S save, ⌘E export.

No. AudioFast is fully offline: no account, no analytics, and the app has no network permission. See the Privacy Policy.

LAME 3.100 (LGPL). Credits are in AudioFast ▸ About AudioFast. Project home: lame.sourceforge.io.