I can pretty much hear any kind of whirring noise, they drive me crazy. I couldn't watch movies on a VCR because I could hear the VCR mechanisms pulling the tape through. Even during movies! On three different VCRs. I've had to sound isolate every desktop computer at work that I've ever used.
I tested over a dozen desktop air circulation fans and bought the quiestest one. Then I took it apart and modified it to make it spin a bit slower.
I could hear the drive spinning in my old 7100 and 510 DVRs, from 10' away. And can do the same on my 622. So I moved the 622 into the basement. That works just great. It was either put it in the basement or get rid of it. It's nice and cool down there too, average temp on it now is 105. But when I'm down there, I can hear it.
I agree that DBS receivers don't fully power down. But the earlier models powered down much more of their circuitry than the new ones do. They spun down their drives and turned off so much that the fans didn't have to run. So they were perfectly quiet when off.