Acoustica is a beautifully designed, comprehensive audio editor built for recording, editing, mixing, mastering and batch-processing.
Audacity is a great open-source audio recording and editing program compatible with most operating systems. The software lets you record live audio through a mixer or microphone; you can also import MP3, WAV, AIFF and OGG file formats -- then, digitize previous recordings, edit them and export.
3- Audio Tool
AudioTool is a great beat-making app, similar to GarageBand. It has a simple, visually pleasing interface, and lets you create complex audio arrangements with more than 14 effects.
4- MP3 Cutter
MP3 Cutter is an audio cutter. In other words, it helps you edit down MP3 files into small audio snippets. Once you've edited the clip, export it as an MP3, WAV or OGG file.
5- Audio Joiner
Audio Joiner is a great app for combining several songs onto a single track. The app lets you cross-fade tracks and adjust certain intervals. There's no limit to the number of songs you combine, and it's compatible with a number of file formats, including MP3, M4A and WAV. It runs entirely online, too, so there's no need to download anything.
Reaper is a compact, downloadable digital audio workstation. Using it, you can record, arrange, edit, mix, layer and render audio. It's non-destructive, so you can undo and redo edits without corrupting your file.
7- Wave Pad
WavePad is free for non-commercial use -- something it reminds you whenever you open the program. It has a clean, modern interface and supports a wide array of file formats. It additionally has a text-to-speech module, lets you rip and burn CDs and comes with tons of editing effects and batch-processing.
Wavosaur is a Windows-only application that lets you record, render and mix audio. The file is extremely small, taking up only 225 KB of storage, but still boasts some of the best features for editing. You can change the bit rates of files, convert file formats, normalize and apply other edits to audio files; plus, the editing process is non-destructive, so you can easily undo and redo any changes.
Nero WaveEditor is an audio processing tool for basic editing and recording. It accommodates AC3,AIF, AIFF, MP3, WMA, MP4, OGG, WAV, WAVE and NWF files. It also allows for non-destructive processing.