need advice to hookup the HT sofa seat with amplified speakers in headset and butt kickers with volume control .. I think the normal way to do this is to hookup through channel outputs (I belive to be sub & center channel rca's) but since I have just bought an ext amp for the reciever the outputs are taken, can I use a rca splitter for the center channel & sub proouts on the amp between exterior amp & sofa seat speakers or is this not a good idea