Audacity is free, open source, cross-platform audio software for multi-track recording and editing.

Features

Recording

Audacity can record live audio through a microphone or mixer, or digitize recordings from other media. With some sound cards, and on any recent version of Windows, Audacity can also capture streaming audio.

• Device Toolbar manages multiple recording and playback devices.
• Level meters can monitor volume levels before, during and after recording. Clipping can be displayed in the waveform or in a label track.
• Record from microphone, line input, USB/Firewire devices and others.
• Record computer playback on Windows Vista and later by choosing “Windows WASAPI” host in Device Toolbar then a “loopback” input.
• Timer Record and Sound Activated Recording features.
• Dub over existing tracks to create multi-track recordings.
• Record at very low latencies on supported devices on Linux by using Audacity with JACK.
• Record at sample rates up to 192,000 Hz (subject to appropriate hardware and host selection). Up to 384,000 Hz is supported for appropriate high-resolution devices on Windows (using WASAPI), Mac OS X, and Linux.
• Record at 24-bit depth on Windows (using Windows WASAPI or Windows DirectSound host), Mac OS X or Linux (using ALSA or JACK host).
• Record multiple channels at once (subject to appropriate hardware).

Import and Export

• Import sound files, edit them, and combine them with other files or new recordings. Export your recordings in many different file formats, including multiple files at once.
• Import and Export WAV, AIFF, AU, FLAC and Ogg Vorbis files.
• Fast “On-Demand” import of WAV or AIFF files (letting you start work with the files almost immediately) if read directly from source.
• Import and export all formats supported by libsndfile such as GSM 6.10, 32-bit and 64-bit float WAV, RF64, and U/A-Law.
• Import MPEG audio (including MP2 and MP3 files) using libmad.
• Import raw (headerless) audio files using the “Import Raw” command.
• Create WAV or AIFF files suitable for burning to audio CD.
• Export MP3 files with the optional LAME encoder library.
• Import and export AC3, M4A/M4R (AAC) and WMA with the optional FFmpeg library (this also supports import of audio from video files).

Sound Quality

• Supports 16-bit, 24-bit and 32-bit (floating point) samples (the latter preserves samples in excess of full scale).
• Sample rates and formats are converted using high-quality resampling and dithering.
• Tracks with different sample rates or formats are converted automatically in real time.

Editing

Easy editing with Cut, Copy, Paste and Delete.

• Find the spot to edit easily with scrubbing and seeking or Timeline Quick-Play.
• Unlimited sequential Undo (and Redo) in the session to go back () any number of steps.
• Edit and mix large numbers of tracks.
• Multiple clips are allowed per track.
• Label tracks with selectable Sync-Lock Tracks feature for keeping tracks and labels synchronized.
• Draw Tool to alter individual sample points.
• Envelope Tool to fade the volume up or down smoothly.
• Automatic Crash Recovery in the event of abnormal program termination.

Accessibility

• Tracks and selections can be fully manipulated using the keyboard.
• Large range of keyboard shortcuts.
• Excellent support for JAWS, NVDA and other screen readers on Windows, and for VoiceOver on Mac in legacy Audacity 2.1.1.

Effects

• Real-time preview of LADSPA, LV2, VST and Audio Unit (macOS) effects.
• Plug-in Manager handles plug-in installation and addition/removal of effects and generators from the menus.
• Generate tones, silence, noise, instruments or rhythm track.
• Change the pitch without altering the tempo.
• Change the tempo without altering the pitch.
• Noise Reduction to remove static, hiss, hum or other constant background noises.
• Alter frequencies with Equalization, Bass and Treble, High Pass, Low Pass and Notch Filter effects.
• Filter a frequency selection created in Spectrogram view or Spectral Selection Toolbar using spectral edit effects.
• Adjust volume with Compressor, Amplify, Normalize, Fade In/Out, Studio Fade Out, Crossfade Clips, Crossfade Tracks and Adjustable Fade effects.
• Reduce or Isolate Vocals given suitable stereo tracks (vocal reduction produces a stereo result).
• Create voice-overs for podcasts or DJ sets using Auto Duck effect.
• Other built-in effects include:
  
  • Distortion
  • Echo
  • Limiter
  • Paulstretch (extreme stretch)
  • Phaser
  • Reverb
  • Reverse
  • Truncate Silence
  • Wahwah
• Run “Chains” of effects on a project or multiple files in Batch Processing mode.

Plug-ins

• Support for LADSPA, LV2, Nyquist, VST and Audio Unit effect plug-ins.
• Effects written in the Nyquist programming language can be easily modified in a text editor – or you can even write your own plug-in.
• Experimental modules that extend the functionality of Audacity.

Analysis

• Spectrogram view mode for visualizing and selecting frequencies.
• Plot Spectrum window for detailed frequency analysis.
• Sample Data Export for exporting a file containing amplitude values for each sample in the selection and Sample Data Import for import of numeric values from a plain ASCII text file
• Contrast Analysis for analyzing average RMS volume differences between foreground speech and background music.
• Support for adding VAMP analysis plug-ins.
• Free and Cross-Platform
  • Licensed under the GNU General Public License (GPL).