From Valve Developer Community
Commercial Software Packages
Shareware and Freeware Software Package
- Audacity audio editor for PC, Mac, and Linux
- Goldwave audio editing
- LMMS (free) alternative to FL Studio! Don't let the name fool you, there's an installer for Windows available (Linux Multi Media Studio)
- Wavosaur free audio editor great for sound looping (Only available for Windows PC)
- Anvil Studio a free MIDI Sequencer. Windows Only.
- SynthFont a free SoundFont-based MIDI player - regardless if you own a SoundBlaster Card - Supports WAV exports (per-track, and as whole audio), and support for VST Instruments
Links of Interest