Thanks John - I tried a BT transmitter/receiver with the latest "low latency" codecs. Apparently, the BT processor has to digitize the audio to send it and then process it at the receive end. Hence there is going to be latency with BT. With the 2.4GHz UHF wireless units (considerably more expensive) the processing delays are minimal - 25ms or less and not noticeable.

In my situation, I am running a Bose Compact with my sax and backing tracks coming from the Bose - I want to wander away from the Bose while it's playing and keep playing along but not lose the ability to hear my tracks as I get further away. I have tried it with BT and there is a big "ping-pong" effect for sure -- nearly 1/2 second delay between the Bose and my portable speaker.

I tried using a wireless vocal mic (plugged the Bose "line out" into the transmitter instead of the lavalier mic) but the signal level on input needs to be cut way back. The Sennheiser DJ relays do the trick - just hate to spend $600 to be able to go that route. I will keep looking around. Thanks for your thoughts!