APG Composer is a free software synthesizer developed by dlab. Available format(s): stand alone application for iOS.
APG Composer combines a 3-voice FM synthesizer with an implementation of the Logique Analogique sequencer, which triggers notes when a weighted sum of different signals exceeds a threshold.
The app was created from a Simulink model without writing app-specific code, using the Audio Plugin Generator source code.
http://www.dlab.ch/