audio delay problem

[sdf]

Hi there- New guy here with probably an old question...

I seem to get a lot of Blu-rays that have audio and video that are not synched together. In fact, some movies seem fine, but then the audio changes as the movies go on. In some cases (Band of Brothers) one disc is fine, but on another I need to adjust the audio delay.

Has anyone else experienced this? It's not a huge deal, as I can always figure out how to adjust it- but it is becoming a bit of a pain. I used to have a Denon 2807 and a 1940 DVD player that had the same problem. So is this a HDMI cable issue?

Here's my set up...

Denon 2808 receiver.
Denon 2500 Blu-ray
Panasonic 50PZ800U Plasma.
Front left and right- Polk RT1000
Sub- Energy S8
Center and 4 surrounds- Monitor Audio Radius

I figure a lot of that doesn't matter, but you guys seem interrested in that sort of thing. Everything is run through my 2808 via HDMI cables from monoprice.

I truly appreciate the help. I'm not familiar with forums, so forgive me if this should be posted elsewhere or the answer is easily found. Thanks!