Bi-amping for HT

Yes you can do it, but I'm not sure why you would consider it. You will still be using the pre-amp section of the ht receiver - no power amp is going to fix that.

Also have no idea what this has to do with bi-amping?

all HT receivers I'm familiar with have pre-outs and will work the way you are asking. The key is this - you want to feed the main outs from your receiver through your your SP-12 preamp in what is called "bypass" mode, and have your main speakers/D-90 amp connected to your SP12 pre-outs.

This setup allows you to use the same main speakers for 2 channel music, and alternately for HT with a simple change of switches. It's not likely to make your HT Fronts sound a lot better (due to the Receiver preamp limitation), but can't hurt it, and greatly simplifies the speaker setup for you.

I doubt your SP12 has true bypass, and if this is true you set up the receiver to feed main outs into a free input on the SP12 (eg tape in). You then set your SP12 volume at a set point that can easily be remembered (eg 12 o'clock), which is where you set it any time you use your HT. Calibrate your HT speakers with the SP12 at this level. You will need to have your SP-12 powered on whenever watching HT. When you want to listen to 2 channel music, simply leave your HT receiver off and run your source through the SP12 as usual.

You can search the archives on "HT Bypass" and find a lot more discussion on this. This is not biamping - which isn't what you're asking about.

As for HT receivers - you should state your budget range if you want some good recommendations. I have a Sherwood Newcastle which was cheap and is stunningly good given what it cost me (~$150 used/mint), though it has some shortcomings.

Thanks for the responses and yes I realize this is not bi-amping, my mistake. I'm just trying to incorporate the ARC 2 channel gear into a HT set-up.

I understand Bdgregory's set-up recommendation but not sure that's a reasonable method given the manuel nature of the SP12, warm-up time, etc. Was really trying to get everything to work off remotes and eliminate the SP12 Pre but it appears that the sound quality will not be so great if the SP12 is replaced by a 'standard' HT receiver Pre.

well, in HT Mode, it will indeed be fully remote controllable. But when in 2 channel music mode, it's the same as you have today.

as Meiwan and I indicated, using the HT Pre for 2 channel music will be a bad idea. I've tried multiple high end HT Pre-Pros and even they don't compare to a good 2 channel preamp when listening to music. An option is to sell your SP12 and by a good remote controllable 2 channel preamp. That's what I did.

Yes, I have considered that but would still like to have the rear speakers for movies and sports. They do fill in nicely but just can't figure out how to keep the rears with the ARC 2 channel gear.

I could go with a nice Marantz or other HT receiver but pretty sure I still won't get that ARC tube sound. If I get a new Pre w/remote that still won't allow for 4 channels, correct?