Alt-tuner is a MIDI retuning plugin designed to expand the expressive possibilities of your keyboard or softsynth by enabling microtonal tuning adjustments. It allows musicians to explore a wide variety of tuning systems, including historical temperaments like Pythagorean and meantone, as well as ethnic scales from Turkish, Arabic, Persian, Indian, and Indonesian traditions. The plugin also supports experimental tunings such as 22 notes per octave and adaptive just intonation that smoothens the sound of conventional music. With an intuitive graphical interface, Alt-tuner is accessible to users regardless of their familiarity with tuning theory, offering presets and simple controls to get started quickly.

Alt-tuner provides flexible real-time control over tuning via mouse, MIDI foot pedals, keyswitches, and various MIDI messages, enabling performers to switch between tunings instantly or modulate tuning dynamically during a performance. Visual feedback through interval displays, lattices, and tables helps users understand and shape their tunings more clearly. The software integrates seamlessly within the recording process as a DAW plugin, allowing full automation of tuning changes throughout a composition. It can retune multiple synthesizers simultaneously, making it ideal for collaborative environments or complex setups. While it does not retune acoustic instruments directly, it supports MIDI conversion workflows to incorporate microtonal tuning into guitar, bass, or violin performances.

Operating as a MIDI-only effect, Alt-tuner modifies MIDI data before it reaches your sound engine, preserving your sound design capabilities while adding the dimension of custom tuning control. It runs within the Reaper environment or through free wrappers on PC and Linux, compatible with a wide range of DAWs via virtual MIDI routing. Alt-tuner is offered with flexible pricing options, including discounted licenses for personal, educational, and small commercial users. Backed by a 30-day money-back guarantee and interest-free financing options, it provides an accessible entry point into advanced tuning explorations for musicians and producers seeking to expand their sonic palette.