Help required please !!!

I have just bought myself a new Sony KDL46HX803 tv aSony BDPS570 blu ray player and a Sony STRDH 810 av reciever all of which has cost a pretty penny.

I have set these up as per the instruction manuals with good quality HDMI cables and included in the set up is my Sky HD box . My problem now is that when the volume on the tv is turned down so we can enjoy the surround sound while wathcing a blu ray movie, the speech form the av receiver and speakers seems to be out of sync to the tv picture this is also happening while watching normal tv programmes via the sky box. I have tried a number of configurations with the cables but as yet had no luck solving the problem. It is becoming increasingly frustrating and my patience is begining to wear just a little thin.

Could anyone offer any advice as to what I can do or try or is it I have gone wrong from the begining. Any comments or thoughts on this matter would be greatly appreciated.