Sound problems with Humax PVR Freesat

[Spannerhead]

I've got the original Humax PVR Freesat box, had it just over a year.

I run the sound through a Pioneer AV amp (4 years old) and Yahama 5.1 speakers.

I've noticed when watching Freesat from the Humax box there is a very tinny (as in tin, not tiny ) sound coming from the speakers, especially bad when people on the TV are talking. When I put my ear to the speaker I can hear a high pitched squeeky distortion, it's driving me nuts.

It's connected to the amp via optical cable. I've tried swapping the cable, no difference. When I play a DVD or a feed from my Popcorn hour, no distortion. If I play the PVR sound out through the basic TV speakers (it's a Panasonic Viera 720p plasma) no problem.

So, I'm assuming it's coming from the Humax box, I've checked my signal strength and it's 95% - so the sound should be fine. Oh yes, and it's on all channels.

Any thoughts?

 

[grahamlthompson]

By all channels do you mean HD channels as well as SD. If so it's very odd as HD channels use Dolby Digital 2.0 or 5.1 a completely different system to sd MP2 sound. What happens if you listen to the BBC HD test card with 5.1 sound check broadcast every day about 10:30 am on the HD preview loop

 

[Spannerhead]

Ahh - haven't checked the HD signal, though I'm sure that's ok as I'm certain I would have noticed the hiss/crackle when watching HD.... I'll check tonite. Thanks

 

[mccg]

I think this is mp2 compression artefacts...

If I am right close to my speakers (5.1 from Onkyo amp via HDMI), I can here a high pitched distorted "shadow" of the normal sound.
It was a lot worse when I had ntl TV.
It probably gets enhanced by things like Pro-Logic.
(It was the same on my old Sony amp)

Edit: It should not be present when watching HD with Dolby Digital/AC3 sound

 

[Spannerhead]

So if that's the case, is there anything I can do? Turn of Pro-Logic?

 

[mccg]

So if that's the case, is there anything I can do? Turn of Pro-Logic?

either that, or just put up with it... or don't put your ear so close to the speaker