SpeedPitch launch screen

SpeedPitch is a simple augmented sonic reality experiment that alters music playback rate based on your actual GPS ground speed. The faster you go, the higher the pitch and sudden stops lead to dragging audio samples. Natural motion leads to unnatural sound.

What Is This Thing, Really?

A media art app.

SpeedPitch is a music player which is controlled by your GPS navigation speed. If the device is not moving, the audio file playback will be very slow. As such, this is not a general-purpose media player but an augmented sonic reality meant to induce exploration into movement and its relation to sound.

This app is best used with bicycles, bluetooth loudspeakers, and lots of friends but will work equally well by foot, car, plane, or even rocket.

User Guide


  1. Select files from the Music app or Files browser using the buttons in the main screen, upper right
  2. Start playback via pressing play or tapping a song in the playlist screen
  3. Ride you bike or take a walk and see what happens...


You can adjust the speed limit for the pitch processing to set the speed songs are played back at a normal rate: menu button, upper right -> Speed. The speed ranges approximate the type of movement you will be doing based on the vehicle.


The playback rate calculation from the live speed updates can be quantized. This basically changes the rate in discrete steps instead of a smooth range which makes matching speed between multiple people much easier.

Keep Awake

Live speed calculations require navigation-level GPS updates which only occur when the device is in active use. If the screen turns off, GPS updates to SpeedPitch will be paused therefore, by default, the "Keep screen awake" SpeedPitch display setting is set to on.


Long-press on the current speed to hide or show the navigation bar and playback controls.


Both the playlist and individual files can be looped automatically. To enable playlist looping, press the loop symbol button on the top of the playlist view. To loop individual files, either swipe left on the file in the playlist and tap the loop button or use the edit mode loop toggle button. Additionally, when the file is playing, tap the loop 1 button on the main screen. When enabled, the current file will loop during playback until another is chosen, ie. by pressing the next button.


July 2021 Nix Wie Raus! Fahrrad Kunst Sommer, Karlsruhe DE


This project has been developed as part of the Nix Wie Raus! Fahrrad Kunst Sommer / Bicycle Art Summer exhibition at the BBK in Karlsruhe Germany 2021.


Originally prototyped using PdParty and a Pure Data patch, 2016-2017.

Playback rate quantization suggested by Ben Miller.