Yes, it's free! ... Download Zap 1.0.0
Zap is a unique mini-synthesiser controlled by incoming audio. It starts with an envelope follower that tracks the peak energy of the sound and then applies it onto the frequency of a monophonic oscillator. With three different oscillator waveform modes and features like envelope stepping, Zap can turn any sound source into dynamic synth sweeps, sub-basses, blips, chirps or glitches.
Zap has a simple and stylish user interface built with colour-coded graphics and full Retina resolution support. It has subtle animations and a live output waveform view, making even such a simple effect very fun and engaging to work with. And yet, thanks to hardware-accelerated rendering, Zap feels fast and responsive even on older, lower-end Macs.
Zap works with Logic, GarageBand, Live, MainStage, ReNoise, Reaper, Studio One, Digital Performer, Tracktion and other software that supports Audio Unit effect plugins. It comes in 32/64 bit format for Intel Macs running OS X 10.6 or later, and supports Retina screen resolution.