iOS Musician Apps (283) Supported Technologies is Inter-App Audio (IAA), Type is Instrument

Relax and instantly create you own meditation music. A great way to explore relaxing vibrations with this spiritually charged music.

Holding the simplicity of a rare 1979 instrument and carrying its raw heritage to you, it turns your device into a pocket beat making companion.

Chordy 2 is a chord player app for music creators.

Laplace is a physical-modeling synthesizer based on resonator synthesis that makes it easy to create bowed string, plucked string, blown pipe and metallic sounds.

Echo Guitar™ Lite is a tool for composing guitar songs.

Mimicking the layout of Hohner's iconic chromatic button accordions (CBA), both B-System (Bayan) and C-System, this intuitive virtual accordion is easy to play and sounds exactly like the real instrument.

Englitina is an authentic-sounding English Treble Concertina for the iPad.

iOS implementation of tunable Balinese Gamelan Gender Wayang.

Annoydio jr has a grid of pads which you can assign, manipulate, and play sounds.

Echo String™ is an innovative harp app.

This is the free trailer version for Percussion Loops HD, percussion sampler for ios

Multilevel Interactive Sound Synthesizer. Up to 240 Frequency Modulation Oscillators or simple Wavetable Additive.

Jam Synth is a fully featured monophonic guitar synthesizer / multi FX for iOS.

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.

iPhilicorda is an emulation of a vintage organ from the sixties, the Philicorda, created by the Dutch company Philips.

Synthecaster fuses elements from guitars and keyboards into a full range polyphonic instrument that is intuitive, accommodates a wide variety of playing styles, and generates an even wider variety of sounds.

AudioKit Synth One is a completely free & open-source professional iOS Synthesizer. 

PolyHarp is a virtual musical instrument and a thought experiment. It's a testbed for harmonic theory as well as a great multi touch simulator of the good old "idiot zither" you have in the attic.

Shape is a polyphonic synthesiser allowing the user to draw the shape of the oscillator waveform.

SoundScaper is an experimental sound mini lab for creating unusual soundscapes, atmospheric textures, drones, glitches and noises based on circuit bending principles.