I put a second disk drive in my Tivo 2 and it emits an annoying "surging" sound with a phase of about one second. It's just loud enough to drive one crazy if you're in the same room and there's nothing else making noise. I didn't use any mounting brackets for the second drive, so that might be worth investing in. But before I placed the order, I thought I'd ask if there's anything else I might try. Thanks!