2.1 out of the needed 5.1

My system was giving me the same problem. But, when I reset the system to the default settings the 5.1 surrond returned. Go to the Preference page in the setup, and change Default to Reset. This will restore all the factory settings, and 5.1 should return.

I would try to figure out EXACTLY what those wires are. First--if you can't open the speaker cabinets without too much trouble, then trash them. Even if you buy some old used stuff, it'll be a cheap upgrade and far less riskier than what you're dealing with now.

Do you have a feel for what quality level you're dealing with? Are these some older exotics that would definitely be worth the trouble? Or are they torn from a boombox or something like that? It still seems odd--even speakers designed for bi-amping would have some sort of connection terminals or binding posts, and bi-amping isn't required--just optional. Hmmm. Even if that IS the case, what would be "proprietary" about that? It's just wire.

You have to be 100% sure you're wiring everything in parallel. Mix serial and parallel, and you've got a short circuit--you could damage your receiver/amp.