Audacity includes some sample plugins by Steve Harris.

Mix tracks with different sample rates or formats, and Audacity will convert them automatically in realtime.

Sample rates and formats are converted using high-quality resampling and dithering.

Record and edit 16-bit, 24-bit, and 32-bit (floating point) samples.

Adjust volumes with Compressor, Amplify, and Normalize effects.

Alter frequencies with Equalization, FFT Filter, and Bass Boost effects.

Remove static, hiss, hum, or other constant background noises.

Change the pitch without altering the tempo, or vice-versa.

Fade the volume up or down smoothly with the Envelope tool.

Use the Drawing tool to alter individual sample points.

Edit and mix an unlimited number of tracks.

Use unlimited Undo (and Redo) to go back any number of steps.

Easy editing with Cut, Copy, Paste, and Delete.

Note: Audacity does not currently support WMA, AAC, or most other proprietary or restricted file formats.

Optional FFmpeg library for import/export of AC3/M4A/WMA and import of audio from video files.

Fast “On-Demand” import of WAV/AIFF files if read directly from source.

Open raw (headerless) audio files using the “Import Raw” command.

Import and export all file formats supported by libsndfile.

Create WAV or AIFF files suitable for burning to CD.

Export MP3s with the optional LAME encoder library.

Import MPEG audio (including MP2 and MP3 files) with libmad.Import and export WAV, AIFF, AU, and Ogg Vorbis files.

Export your recordings in several common file formats. Import sound files, edit them, and combine them with other files or new recordings.

Level meters can monitor volume levels before, during, and after recording.

Record up to 16 channels at once (requires multi-channel hardware).

Dub over existing tracks to create multi-track recordings.

Record from microphone, line input, or other sources.

With some sound cards, it can also capture streaming audio. Audacity can record live audio through a microphone or mixer, or digitize recordings from cassette tapes, vinyl records, or minidiscs.

Audacity free audio editor