Hi Guys, thought I might be able to lend a hand regarding the Lip Sync issues people are having with the LE46C750 3D TV and with Blu-Ray surround sound systems.
I have just purchased the TV with a Samsung HT-C5800 2.1 3D Blueray Home Cinema system, and connected Virgin Media HD box. I had the syncing issues when the home cinema was connected to the HDMI 2 (ARC) input on the TV, and the Virgin Media using HDMI 3 input, with an optical connection from the TV to the bluray home cinema.
I fiddled around in the audio settings menu - pressed the Enter button on the remote to get the 'Additional Settings' menu, and found the TV had the optical SPDIF delay setting default at 110ms. I reduced this to 0ms and now the whole system is working perfectly in sync, even with the cheap virgin HDMI lead.
My 3D BluRay home cinema is however connected using Monster Cable 1200 HDMI which supports Audio Return Channel and all that jazz (ARC I Believe.) Not sure if thats why I no longer had issues, but changing the delay on SPDIF to 0ms definitely solved the problem. Very happy now!
Hope that helps!
Mike.