CycleSync is a free app that keeps dozens of sound systems playing in lockstep using a shared GPS clock. It's brand-agnostic, so JBLs, Soundboks, and custom rigs all play together: no range limits, no breaking up when line of sight is lost, and no audible lag between speakers.
A group ride usually sounds like a dozen speakers fighting each other. CycleSync makes them one: every unit starting the same song on the same beat, so the ride moves like a rolling nightclub.
CycleSync doesn't care what you plug in. A JBL here, a Soundboks there, a custom high-power rig up front: they all lock to the same track and play as one. Bring whatever you've got.
Download CycleSync free from Google Play. On Android that's the whole setup: nothing else to buy. The iPhone version is still in development.
Every speaker takes a slightly different amount of time to turn a play command into sound. A one-time calibration measures your setup's delay so the app can offset playback to cancel it.
By using GPS, every phone shares one precise clock to synchronize playback against.
Run an aux cable to your speaker, create or join a room with a short code, and hit play. Every speaker plays the same track, aligned to the millisecond.
CycleSync feeds your speaker or amplifier through an aux cable, never Bluetooth. Bluetooth adds unpredictable latency, and that lag between speakers is exactly what breaks a group's sync.
Android lets apps read the phone's own GPS timing directly, so CycleSync locks to GPS time with nothing but the app. Any modern Android phone works out of the box; no extra hardware to buy or carry. It's on Google Play now, free.
There is no iPhone version yet, and when there is, it will need the handlebar module. iOS doesn't give apps direct access to the GPS receiver's raw timing, even with location permission enabled. That's the gap the module fills: a large, sky-facing antenna that feeds a rock-solid GPS clock over USB-C, so iPhones can stay locked to the same precise time, even in dense, obstructed urban conditions.
The CycleSync module mounts on your handlebars, feeds the app a precise GPS time reference, and gives you an audio output to your speaker.
The iPhone app and the module are both being designed now. There is no date to give yet: when there's a prototype worth riding with, it'll be here. Android riders won't need any of this; the free app already syncs on its own.
Free on Android, on Google Play now. Calibrate, create a room, queue the music, and call out to the whole ride, all from the phone already on your handlebars.
Turn a scattered string of speakers into one wall of sound. Everyone hears the same drop at the same moment, front of the ride to the back.
Queue the playlist before you roll out, hit play once, and make announcements over the music, on every speaker at your ride.
CycleSync for Android is on Google Play now. The iPhone version and the USB-C module are still being built. If you've ridden with it, I want to hear how it went: what drifted, what broke, what worked. And if you lead rides, run a sound system, or just want to follow along, get in touch.
The app is free and stays free. The servers behind it cost money every month: if you want to help with that, there's a support page.