brewerd

I'm looking for some speakers that sound good and are truely wireless. All the ones I've seen use batteries or require an ac adapter which essentially makes them wired. Is there a technical limitation that would keep them from being made with the plug built into them so they could just be plugged directly into an outlet. I have a set of Quintets now and would like them to sound as least as good as those but all the wireless ones I've seen so far are in the sub $200 range.