I use Phonak's tvLink and iCom, but the following applies to any "streamer" or cordless audio transmitter/receiver pair. When my wife and I watch TV together, the ~4ms lag between the iCom and the stereo loudspeakers was disturbing. Can be eliminated by cabling the tv lineout or headphone socket to the iCom, but then you're tethered. Or by using an expensive 863mHz transmitter/receiver set (Sennheiser RR 840 S - but that has to be plugged into the iCom and carried around with you too. Did that for a while. I found the tvLink sounded better and wanted to be free of the Sennheiser receiver hanging off the iCom around my neck. Found this:
RTS-200C RADIOTVSYNCTM STEREO AUDIO DELAY WITH REMOTE
[RTS-200C] from Don Moser (Motron)
. Hooked it up between tv analog audio out and stereo audio in, matched the bluetooth delay to the millisecond - perfect.
Costs about $200. Advantages: better quality sound via bluetooth A2DP than with analog FM or cable, exact
compensation for latency due to distance from speakers or any other cause, not having a second device or cable attached to the bluetooth receiver around one's neck. And
you can also use it for its original purpose - listening to local radio broadcasts of sports events on TV, synching audio and video. (Video is usually delayed by some seconds.) (I had to remove 2 urls because I'm a newbie - but y'all can google them easy.)