FM4 is a four operator FM synthesizer for iPad. Modelled on the first commercially available FM synths from the 1980s FM4
provides the same gritty sound, with a modern interface, and without being bound by the limitations of the original units.
For example we have thrown in an arpeggiator, a thick unison mode, and a pitch envelope with a tweakable curve ideal for
percussive sounds. Thus FM4 is capable of producing a multitude of sounds, ranging from punchy basses, crystal-clear bells,
and lush pads, to organic textures, striking drums, and piercing leads.

FM4 features

- 4 operators, configurable via eight different routings.
- 3 sound engines modelled on 1980s hardware units.
- 8 waveforms derived from classic FM synths.
- Unison: 2x, 3x, and 4x — works in polyphonic mode.
- Microtuning with eight different temperaments.
- Arpeggiator, tempo-syncable with up, down, up-down, and random patterns.
- Connectivity: supports Inter-App Audio, Background Audio, and MIDI (Audiobus is planned).
- Polyphonic: 8 voices on iPad-mini/iPad 2, 24 voices on iPad Air.
- 128 Presets organised into eight banks — user presets can be imported/exported through iTunes.

The app is available for purchase for the introductory price of $0.99 USD through December, 2014.

More information: Primal Audio