Audacity
Record and play sounds, import and export WAV, AIFF, and MP3 files, and more.
Available for Windows, Mac, and Linux, the free audio editor Audacity lets you edit sounds using Cut, Copy and Paste (with unlimited Undo), mix tracks together, or apply effects to your recordings. Audacity features a built-in amplitude envelope editor, a customizable spectrogram mode, a frequency analysis window for audio analysis applications, and support for VST plug-in effects. Built-in effects include Bass Boost, Wahwah, and Noise Removal. Newer features include an "Inverse RIAA" equalization preset, more intuitive behavior when moving and resizing labels by dragging, new hover tooltips, and improved export options.
