Just experiment Junior, like I did, with and without audio and with receiver at a distance to get the best sound you can.
Antenna position, including being as far from sources of interference (power cords, power supplies etc) is also a big thing to consider.
Jason insists that you need to use the Soundblaster. I don't know if he has stock in Creative I get similar output from an even cheaper USB sound module...
lol, maybe he does.
I didn't notice any difference between my laptop sound card and the soundblaster, but others have said the soundblaster is an improvement over the built-in Pi sound chip.
the cze-05b has a little instruction leaflet , I had the same issue , the fix was to turn the volume down out of the pi and use the volume on the transmitter to adjust , I think if you have the volume too high on the pi/pc it overdrives the transmitter