Ardour: Professional Digital Audio Workstation

Ardour is a hard disk recorder and digital audio workstation application.

Ardour's intention is to provide digital audio workstation software suitable for professional use.
As Ardour is a free and open source software application anyone can read and modify the source code of the program. This allowed the first port of Ardour to Mac OS X to be carried out by someone previously uninvolved with the Ardour project. Ardour attempts to adhere to industry standards to maximize functionality and ease portability.





Some of its features: 

• Unlimited audio tracks and buses
• Non-destructive, non-linear editing with unlimited undo
• Anything-to-anywhere signal routing
• Unlimited pre- and post-fader plugins
• 32 bit floating point audio path
• Automatic track delay compensation
• Sample accurate automation
• Standard file formats (BWF, WAV, WAV64, AIFF, CAF & more ...)
• Full AudioUnit plugin support on OS X
• More than 200 LADSPA & LV2 plugins freely available
• Support for Windows VST plugins available
• MIDI CC control with 1 click
• Level 2 MIDI Machine Control
• MIDI Timecode (MTC) Master or Slave
• Full integration with all JACK applications
• Video-synced playback, pull up/pull down 

• No copy-protection
• Distributed, world-wide development
• Released under the GPL
• Source code for everyone
• Open XML session file format
• On OS X, works with any CoreAudio supported audio hardware
• On Linux, works with any ALSA/FFADO-supported audio hardware
• Network audio (full fidelity over local network or long haul with CELT) via NetJack

Ardour can be used on  Linux, Mac OS X and FreeBSD and is available for download in most distributions' repositories.

Or you can download it at their website ardour.org