Wow, as usual Gonk, you've got a lot of good suggestions.

What I'm doing now is running analog out to the 970 from my CD player. I assumed the performance from the DAC, etc. in my Cambridge Audio 640C CD player was an improvment over the digital processing available in the 970, but I could be wrong. I know that may not the case with the 990, which has superior digital processing than the 970 (if I remember correctly). Anyway, I could hook up the digital output and do an A/B comprison to verify.

As to the 7.1, HPF/LPF option you described, is that available only in the DVD input? With a DVD player currently hooked into the DVD input I would prefer not sacrficing it to the CD player... Or am I following your train of thought correctly?