Open Tuning is a Midi utility offering to MIDI and MIDI-fied polyphonic instrument players (such as guitarists and violinists) the ability to play and explore an unlimited number of virtual tunings without needing to retune their instrument each time.

Main features

• The built-in Mac OS X Audio-Unit DLS Soft-Synth can be chosen
  and played from within Open Tuning through a user-friendly
  interface
• Tuning Presets Files included
• Tuning Presets can be controlled by Program Change
• Real-time processing thanks to Apple's CoreMIDI technology
• User can freely configure and play simultaneously up to four
  instances of Open Tuning
• Adds four internal MIDI ports (2Inx2Out) per instance for rewire
  with soft-synths as plug-ins or standalone applications
• User can create its own tuning presets
• Snapshot feature to store and recall a tuning preset
• Help tags available over each user interface elements