Wavepad

WavePad is a very interesting program that can make multiple edits to your audio files. With it, you can copy, cut, and modify an audio sequence however you like.

The graphical representation of the sound waves makes it much easier to work with the files. Some of the changes that can be made are: amplify, normalize, equalize, reverb, echo, fade in, fade out, envelope, reduce noise, etc. You can also change the speed and pitch of an audio sequence in three different ways.

WavePad includes other interesting tools, some of which are not included at first but can be download for free on the developer's website.

You can use WavePad as a tone generator, a voice synthesizer, and a text-to-word tool. With this program you can also create predefined sets of actions to simplify working with multiple files.

Supported formats are WAV, MP3, WMA, VOX, GSM, AU, RM, and some others. It supports samples from 6000 to 96000Hz, in stereo or mono, and in 8, 16, or 32 bits.