A bank of cascaded-triple-oscillator frequency modulation (FM) synthesizers provides a broad palette of sounds from percussion to strings.

The keyboard can be scrolled across the full 88 keys of a piano from A0 to C8. You can even change the size of the keys to suit the size of your fingers. The keys are touch sensitive - the harder you tap a key the louder the sound.

A single bar controls the app. The outer "<<" and ">>" buttons loop through 16 control functions:

• Patch
• Portamento (for "sliding" from note to note)
• Register (octave) shift
• Number of white keys in view
• Amplitude attack
• Amplitude decay
• Modulator 1 attack
• Modulator 1 decay
• Modulator 1 frequency ratio
• Modulator 1 modulation index
• Modulator 1 and dynamic modulation
• Modulator 2 attack
• Modulator 2 decay
• Modulator 2 frequency ratio
• Modulator 2 modulation index
• Modulator 2 and dynamic modulation

The inner "<" and ">" buttons loop through the setting for each function; e.g., for "Amp. Attack" there are 4 settings: "shortAmpAttack", "mediumAmpAttack", "longAmpAttack", and "veryLongAmpAttack". In all there are over 170 million different sound setting combinations.

The FM frequency ratio defines the harmonic frequencies, modulation index controls the number of harmonics, and dynamic modulation defines how the harmonics change in time.