Audacity is free, open source software for recording and editing sounds. It is available for Mac OS X, Microsoft Windows, GNU/Linux, and other operating systems.

You can use Audacity to:

• Record live audio.
• Convert tapes and records into digital recordings or CDs.
• Edit Ogg Vorbis, MP3, WAV or AIFF sound files.
• Cut, copy, splice or mix sounds together.
• Change the speed or pitch of a recording.

Editing

• Easy editing with Cut, Copy, Paste, and Delete.
• Use unlimited Undo (and Redo) to go back any number of steps.
• Very fast editing of large files.
• Edit and mix an unlimited number of tracks.
• Use the Drawing tool to alter individual sample points.
• Fade the volume up or down smoothly with the Envelope tool.

Effects

• Change the pitch without altering the tempo, or vice-versa.
• Remove static, hiss, hum, or other constant background noises.
• Alter frequencies with Equalization, FFT Filter, and Bass Boost effects.
• Adjust volumes with Compressor, Amplify, and Normalize effects.
• Other built-in effects include:
  • Echo
  • Phaser
  • Wahwah
  • Reverse

Sound Quality

• Record and edit 16-bit, 24-bit, and 32-bit (floating point) samples.
• Record at up to 96 KHz.
• Sample rates and formats are converted using high-quality resampling and dithering.
• Mix tracks with different sample rates or formats, and Audacity will convert them automatically in realtime.

Analysis

• Spectrogram mode for visualizing frequencies.
• “Plot Spectrum” command for detailed frequency analysis.