1.Audacity
Audacity is free, open source software for recording and editing sounds. It allows you to record live audio, converts tapes and records into digital recordings or CDs, edit Ogg Vorbis, MP3, WAV or AIFF sound files. You also can cut, copy, splice or mix sounds together with Audacity. Built-in effects are given to remove static, hiss, hum or other constant background noises.
2.Power Sound Editor
Power Sound Editor Free is a visual audio editing and recording software solution, which supports many advanced and powerful operations with audio data.
You can use Power Sound Editor Free to record your own music, voice, or other audio files, edit it, mix it with other audio or musical parts, add effects like Reverb, Chorus, and Echo, and burn it on a CD, post it on the World Wide Web or e-mail it.
3. LMMS
LMMS is a free cross-platform alternative to commercial programs like FL Studio, which allow you to produce music with your computer. This includes the creation of melodies and beats, the synthesis and mixing of sounds, and arranging of samples. You can have fun with your MIDI-keyboard and much more; all in a user-friendly and modern interface.
4.Qtractor
Qtractor is an Audio/MIDI multi-track sequencer application written in C++ with the Qt4 framework. Target platform is Linux, where the Jack Audio Connection Kit (JACK) for audio, and the Advanced Linux Sound Architecture (ALSA) for MIDI, are the main infrastructures to evolve as a fairly-featured Linux desktop audio workstation GUI, specially dedicated to the personal home-studio.