Of course this assumes that your subwoofers have a built-in line level crossover that has a high-passed output to feed the power amplifier for the main speakers
I'm glad this solution works for you. While you can run the output of your pre/pro first to your sub's analog crossover, and then back to your amplifier, and then on to your main speakers, I'd rather use the digital crossover in a modern pre/pro's, especially for the MAIN speaker channels. Modern pre/pro's have much cleaner bass management than the analog line level crossovers in a subwoofer. And there is the (I assume) long analog signal path from pre/pro to subwoofer to amplifier (to main speakers) to consider. But bottom line is this works for you, and that's what's important. I'm glad you have a solution that works for you.
Set the subwoofer's crossover to 60 or 80 Hz, depending on the size of your mains.
The 60 Hz and 80 Hz digital crossover in modern pre/pro's is quite good. The bass managment in modern pre/pro's is much better than bass management I heard from some receivers only a few years ago. Of course a few years ago, many didn't even have 60 Hz crossovers.
[This message has been edited by Will (edited August 14, 2002).]