The receivers constantly monitor for interference and periodically hop to different frequencies to avoid it. The idea here is to add these components to an existing system. The ARW51's price of $700 won't be a whole lot cheaper than the $900 original product, which also included five speakers and a subwoofer. So it's not exactly a money-saving option. But if you love the speakers you already have (i.e. they are expensive suckers), this is a way to make them wireless.