This project is a very simple tool to help determine audio delays using bluetooth headphones or bluetooth earbuds. Written purely in HTML / JavaScript. Maybe I'll make a simple ElectronJS/Desktop app out of it at some point.
Press the Start / Stop button and it will play the music and start the millisecond timer at the same time. Press it again to stop the music playback. You can do this several times and record them all in a table. There is also a running average displayed.
Many cheaper Bluetooth headphones/earbuds have audio latency. The idea is that you click/tap to start the music and then you click/tap to stop the timer as soon as you hear the music actually coming through. If you've got higher end earbuds/headphones this sort of delay may not even be noticeable. Also, with advances in Bluetooth technology this may not exist as a thing in the future at all.
You can use the tool right here on GitHub. Enjoy!
https://jjaeger4.github.io/BluetoothHeadphoneLatency/
The music file comes from the no license needed section of the YouTube creator studio. It is called "Floating Also"