Bluetooth audio delay / lag, reason completely unclear to me
I have a bit of an odd situation, and wanted to ask for ideas.
Recently started connecting a JBL Charge 2+ to my MBA 11 inch, mid-2013, via Bluetooth. I noticed that there's clear delay between sound event and sound being audible via the JBL.
The problems persists across applications (so for example, playing video via VLC means the sound isn't synced, same for youtube videos in different browsers, same for mp3s that start playing with a small delay, etc.)
The delay is minor, but noticeable, in the range of 0.5s I'd say.
At first I thought it might be a Bluetooth driver issues, but now I found out the following: just connected another JBL device, a Flip 3 to the same MBA, and the sound plays without noticeable delay. I'm not sure if they use the exact same drivers, but now I'm wondering:
Is there a chance that it's a hardware problem? Didn't really consider this a possibility, but now I'm not sure anymore.
How to test, and, ideally, fix this issue? How can I isolate the reason for the audio lag with the Charge 2+?
Any help would be appreciated!
Bluetooth lag is a known problem with some, but not all, remote speakers, headsets, etc. We have several Vizio sound bars that have a definite lag, but a Harmon-Kardon speaker set that doesn't. In some cases, adjusting a specific Bluetooth system parameter in Terminal can help with the lag. This works on some of our Vizio sound bars, but we had to hard-wire others to guarantee no video syncing issues.
sudo defaults write com.apple.BluetoothAudioAgent "Apple Bitpool Min (editable)" -int 40
The -int value can be experimented with to troubleshoot, but I'd be cautious and not be too extreme in the values you try.
I found this information at this link and this one.
This is issue with the speaker. JBL Charge 2 and Charge 2+ have lag even in the wired AUX input, because it does signal processing with DSP instead of being a simple analog amplifier! JBL Charge 3 does not have the lag in AUX input. I am not sure if bluetooth of Charge 3 is less laggy or not, but chances are that also has improved latency due to newer bluetooth standards and the DSP apparently being faster / less buffering.