whenever i listen to older cds, say from the late 80s, after listening to a new release, i notice a significant drop in volume. the question is, is this due to hotter mixes or is the information encoded onto the cd degenerating? i remember reading an article saying that vinyl lps don't degenerate as quickly as cds. i suppose this isn't taking into consideration wear and tear on the vinyl. any corroborations or refutations?