WavePadfor Mac

WavePad is a fully featured professional audio and music editor that allows you to record and edit music, voice, and other audio recordings. With this free software, anyone can meet all their music editing needs on Mac. You can add a variety of effects such as echo, amplification, and noise reduction. WavePad supports a wide range of formats including WAV, MP3, VOX, GSM, WMA, Real Audio, AIF, FLAC, and OGG. The great thing is, it's absolutely free, although it does offer you the chance to upgrade to WavePad Master's Edition which has additional effects and features.

This free version of WavePad supports sample rates from 6000 to 96000Hz, stereo or mono at 8, 16, 24, or 32 bits. It also includes an integrated CD ripper to save your creations. Additionally, you can have fun with the voice synthesizer which can give your voice a robotic effect. The overall interface is clearly laid out and easy to use, with tabs to flip from edit to edit and a handy magnification tool for precise edits.

There are even more interesting effects available in the Master's Edition, but as a mid-range audio editor that's easy to use, WavePad is an excellent choice.