WavePad

WavePad is a full-featured professional sound editor. It lets you make and edit music, voice and other audio recordings. When editing audio files you can cut, copy and paste parts of recordings and, if required, add effects like echo, amplification and noise reduction. WavePad works as a wav editor or mp3 editor but it also supports a number of other file formats including vox, gsm, real audio, au, aif, flac, ogg and more.

• Sound editing functions include cut, copy, paste, delete, insert, silence, autotrim and more.
• Audio effects include, amplify, normalize, equalizer, envelope, reverb, echo, reverse, sample rate conversion and more.
• Supports a number of file formats including wav (multiple codecs), mp3, vox, gsm, real audio, au, aif, flac, ogg and many more.
• Batch processing supports up to 32000 files allowing you to apply effects and/or convert your files as a single function.
• Tools include spectral analysis (FFT) and speech synthesis (text-to-speech).
• Many more features.