It sounds like crackling, popping in the background. It's apparently called digital clipping and is introduced during mixing/mastering because the guy doing it don't care about the sound, only that it's load enough so they crank it all the way until it clips and information is lost, ruining the sound. That's what I gather from that hifi thread anyway.I must be deaf or stupid, I listened to that part three times in a row and I have no idea what you or the people on that forum are talking about.
(As for Still Life, it is there but much less noticeable than in Celts and The Parchment, where it's horrible. It's the same on Hell on Earth as well by the way)