WavePad is a sound editor program for Mac OS X. This software lets you make 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.

Sound editing functions include cut, copy, paste, delete, insert, silence, autotrim and more.
Audio effects include, amplify, normalize, equaliser, envelope, reverb, echo, reverse, sample rate conversion and more
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.