Chromecast Audio out of sync with Youtube Tab on PC

[garyrbeach]

I use a wifi connected Asus desktop and cast music (Pandora tab) to 2 Logitech UE Boom speakers(set up as a "group"). This works fine.
My problem is when I want to show a Youtube video on the PC and cast the audio to the speakers. Very out of sync.

These are bluetooth speakers, but, alas, the bluetooth connection was dropped so frequently I had to buy Chromecast Audio to even use these speakers.

I'm aware of the ability to sync the 2 speakers within the group (latency correction), but that is not the problem. I want to sync the video on the PC to the sound on the Booms.

Any ideas?

 

[garyrbeach]

Me again with a little more info. This problem is with all streaming video, not just Youtube. The PC is 4' from modem and the speakers are 15' and 35; away from modem.