Audacity is a free audio editor. You can record sounds, play sounds, import
and export WAV, AIFF, and MP3 files, and more. Use it to edit your sounds
using Cut, Copy and Paste (with unlimited Undo), mix tracks together, or apply
effects to your recordings. It also has a built-in amplitude envelope editor,
a customizable spectrogram mode and a frequency analysis window for audio
analysis applications. Built-in effects include Bass Boost, Wahwah, and Noise
Removal, and it also supports VST plug-in effects.