I have a question regarding speakers that maybe someone could help me with. When I first got into home theater, I bought an RCA "home theater in a box". It came with 5 6ohm speakers. Over the last year or so, I have been upgrading components. I recently purchased a Denon 2802 receiver with DTS-ES. It supports speakers with impedance of 6-16ohms. Here is what I want to do. I would like to purchase a new center channel and use the old RCA one as the Back surround channel. A new center will most likely be an 8ohm speaker, while all of the others will be 6ohm. Does anyone know if the receiver would have a problem with this or is it not a good practice? I have no idea on this one so if anyone has any advice I would appreciate it. Thanks!