Show HN: Beatsync – perfect audio sync across multiple devices
freemanjiang Tuesday, April 29, 2025
Hi HN! I made Beatsync, an open-source browser-based audio player that syncs audio with millisecond-level accuracy across many devices.
Try it live right now: https://www.beatsync.gg/
The idea is that with no additional hardware, you can turn any group of devices into a full surround sound system. MacBook speakers are particularly good.
Inspired by Network Time Protocol (NTP), I do clock synchronization over websockets and use the Web Audio API to keep audio latency under a few ms.
You can also drag devices around a virtual grid to simulate spatial audio — it changes the volume of each device depending on its distance to a virtual listening source!
I've been working on this project for the past couple of weeks. Would love to hear your thoughts and ideas!