The next generation of Arithmophones is on Android and iOS! The first of a new series of touchscreen musical instruments is Pentatone, available now as a free app (no in app purchases, no ads or data collection) from the Apple App Store and Google Play Store:
Pentatone is a music app featuring an expressive keyboard and a built-in synthesizer with a custom sound engine. The name Pentatone comes from the Greek words πεντᾰ (pentă; five) and τόνος (tónos; note) and the keyboard is focused on pentatonics: musical scales with 5 notes per octave. You can use it as an easy-to-play instrument, a source of melodic and harmonic inspiration or a tool for learning about music and exploring the deep connection it has with numbers.
Most music creation apps either give you piano keys or a grid-based interface. Pentatone takes a fresh approach, optimised for the ergonomics of touchscreen devices and inspired by instruments like the kora and mbira. It also features a sophisticated scale selection system that includes all the common pentatonic scale types and unlocks some more unusual ones.
Pentatone features:
- Easy-to-play “strummable” waterfall keyboard, split for two-handed playing
- Original pentatonic scale system with 9 selectable scales, in just intonation or standard tuning
- Custom synth engine (binaural 2×2 operator FM with stereo detune, resonant filter, delay and reverb)
- 25 preset sounds with macro sliders for tone and ambience
- Initial touch and aftertouch response, both polyphonic
- AUv3 plugin functionality for use within host apps like GarageBand, Koala Sampler and Loopy Pro (iOS only)
Click here to install Pentatone on your iPhone or iPad, or here to install it on your Android device.
An Arithmophone is a thing that turns numbers into sounds. Its name is derived from the ancient Greek words ἀριθμός (arithmos; number) and φωνή (phone; sound). For links to earlier versions of the Arithmophone and more background information, please visit this page.
Arithmophone concept, design and development by Chiel Zwinkels © 2026