I need help. I want to add some high zip to my existing speakers by connecting an additional tweeter which would sit on top of each main speaker box. The impedance of the tweeter is 4 ohms and the impedance of my main speakers is 8 ohms. My receiver is rated for an 8 ohm speaker output only. Can it be done? The tweeters are bullit-type design, made by Pyramid, and are reasonably priced. Is it worth it?