iOS Musician Apps (132) Supported Technologies is Inter-App Audio (IAA), Instrument Type is Synth

SynthDrum Pads 100% synthesized signal path, Virtual Analog Drum Synthesiser, with 32 step sequencer.

Ribbons is an extraordinarily fun and expressive musical instrument for iPad.

Vox Unit is a vocoder. You speak in the microphone, you play on the keyboard, and choir and vocal effects are produced.

This is a synthesizer designed specifically for making Dubstep, DNB and EDM lead bass/synth.

Droneo is a synthesizer which drones with various timbres and precise intonations that blur the distinction between tones, timbres and chords. Its drone is great for meditation, centering, and calming,  walking and biking, but also can be set up for discordant noise and insect-like buzzing and chirping.

Phawuo is a monophonic virtual-analog synth with "dirty" oscillators. Good for bass sound and effects.

Arpeggist is a MIDI Note arpeggiator with a very flexible step matrix editor for programming and a unique “rolling dice” random arpeggio generator.

PixiTracker 1BIT is a simple and fun tool to quickly create musical sketches, chiptunes and experiments with TRUE 1-BIT SOUND (like on old microcomputers).
No musical knowledge required.

An app which is a faithful digital re-creation of their circa 1980 analog cult-classic, The MINI-SYNTHESIZER.

SpringSound is a physical-modeling audio synthesizer that produces sounds by simulating interactions and vibrations of a set of activators and masses connected to springs.

AnalogKit lets you play, share, and build synths and effects in an incredible digital playground.

Cube Synth is a groundbreaking new software instrument giving you the power and flexibility of additive synthesis together with easy editing and morphing capabilities.

The unique dynamic wavetable synthesis allows you to explore an unprecedented wide range of sonic territory.

Pixound provides a deep musical experience that lets you instantly create music using any picture.

Tera Synth is a Modular Analog Synthesizer.

PixelWave is an experimental synth with old school pixel interface.

iStatic generates continuous visual and aural noise. Use it to mask distracting background sounds, when you're at work, reading on the train, trying to sleep, or if you just loathe silence.

Photophore is a unique instrument that uses flocks of up to 100 sound generators to create rich, organic synthesizer sounds.

SpectrumGen is a spectral synthesizer with a simple and effective user interface.

Mynth is the new intuitive and powerful synthesizer by Fingerlab.