Crackling audio on P4 recordings

We're experiencing some very faint but annoying crackling sounds on recorded shows (across many cable channels - so it seems universal). It's only noticeable in quiet areas of shows - otherwise it's covered up by the regular audio that's a lot stronger/louder.



The cracking is recorded - it plays exactly the same crackle pattern in the same spot on playback, so it's not a audio playback system problem - of course there are many non-Tivo things to try to blame - HDMI cables, cable card, cable splitters in the attic, cable runs themselves, cable tuning adapter (Brighthouse) - though there is no evidence the crackling has anything to do with the TV - nor do we experience it watching cable TV directly via the Tivo P4, which is used as a tuner with the cable card installed. It only seems to happen in the audio of played back recordings, not in the audio that goes "through" the Tivo. So what else could it be but something in Tivo hardware?



Any ideas? Suggestions welcome.



We are in Year 2 owning this box (w/Lifetime) - thankfully we bought the 3 Year Warranty, if it is defective. Bummer though if we have to send it in as we really wouldn't want to miss out on days to weeks of recording shows while it's in surgery. We would lose our TV tuner too. :-(