From NCH Software: WavePad Sound Editor for Mac OS X lets you record and edit voice and other audio recordings. You can cut, copy and paste parts of recording and, if required, add effects like echo, amplification and noise reduction. Special effects include reduce vocals, distortion, chorus and more. Batch processing allows you to apply effects and/or convert your files as a single function. Audio restoration features including noise reduction and click pop removal. Recorder supports autotrim and voice activated recording.

Create and work on multiple audio files at one time and save them as one project. Supports sample rates from 6000 to 96000Hz, stereo or mono, 8, 16, 24 or 32 bits. Pre-defined audio quality suggestions when saving files such as CD Quality and Radio Quality. Tools include spectral analysis (FFT) and speech synthesis (text to speech). Load audio files directly from CD and convert to .wav files automatically. Allows you to set user assigned keys and macros. Set bookmarks along multiple files as you work.

What do you need to know about free software?