iOS Musician Apps (47) Instrument Sounds is Keyboards, Free

LCW-2 mono is a little complicated synthesizer based on ToyTone and implements several experimental functions.

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

Modulin is a customizable synthesizer. It allows for unique personal expression while providing a wide spectrum of visual feedback.

Wotja X is a new cross-platform interface for the 'Wotja Generative Music System'.

Free iPad instrument featuring the classic sounds of famous 80s FM Synthesizers.

Groovebox is a free music studio app packed with synths and drum machines.

Beatonal is an accessible music making app, enabling you to easily create and share your musical ideas using the built-in synthesizers and drum machine.

Featuring an FM tone generator, FM Essential is a synthesizer app that provides for real-time synth performances and also lets you edit voices.

Dedicated monophonic synth bass synthesizer.

Turbosounds for Accordion provides many special sounds of the Oberkrainer folk music.

A strange noise-making device.

AutoArp turns your iPhone (or iPod Touch) into a musical instrument that is halfway between a traditional auto-harp zither and an arpeggiated analogue-style synth.

Make music in seconds. Share, remix and collaborate with music makers all over the world.

SynthMaster Player for iPad is the MOBILE PLAYER VERSION of the award winning SynthMaster software synthesizer.

Chiptunes Pro lets you make retro music the way it should be made - with chips. Build your circuit to lay down drum beats, basslines, and tunes.  No knowledge of electronics needed.

Nanologue boasts a wide scope of inspiring sounds and professional sound effects, sporting a straightforward multi-touch interface and a great-sounding monophonic synthesizer.

Dandy is a sampler/synthesizer for iPhone inspired by Dandy Desmonds composition “Magnetic Loops for 15 Tape Decks” from 1938, which is one of the earliest known works of electroacoustic music.

Colossus Piano sets a new standard in terms of realism, detail and overall quality of piano sounds on your iPad, iPhone and iPod touch.

Electric piano sampler.

VOSIS is a synthesizer that uses scanned synthesis of greyscale image pixel data from photos or live video input. It is also a tool for image audification/sonification and visual music performance.