What are some good wireless adapter for surround-back speakers for less than $100? Currently, I have 7.1 setup, KEF R11 as fronts, and JBL 530 as back and surround. One of the surround-back speaker's wire is on the floor in the walkway. I mostly only use 2.1 and listen to music about 70% of time. 30% for movies and I don't care about the very minor difference in the surround-back because of wireless. So, I don't want to spend a lot on this wireless adapter. please let me know.