Denon 4500 no bluray sound

[Garp]

Hello all, I have recently purchased a Denon x4500h to replace my 2011 Onkyo 609 which wasn't 4k 2.2.
I have it connected to my LG C8 with HDMI via both ARC input/output.

Netflix from TV app is fine on TV audio source and Dolby Atmos appears on screen when Atmos source is put through it which is great!!

My Xbox One X is fine too, Also says Atmos

The problem Im having is no sound from my older Sony s790 bluray player.
It worked for a while as I tested last Jedi with new Amp!.
It was fine with the Onkyo also.
I then decided to take the player up to my bedroom tv and again no sound. I reset all settings and joy, sound came back. I then took player back down this morning, replugged into my amp and tested it. Damn, no sound again.
My even older Sony s360 works but soooooo slow and picture grainy so that remains in bedroom.
There was also weird handshake issues and when trying to test the s790 this morning the amp keeps flicking to tv Audio/ARC HDMI which is highly frustrating.

Can anyone help with all this as its driving me mad. I don't want to buy a new 4k blu ray until maybe the UBP-X800M2 with dolby vision comes out and is reduced in price. The xbox is fine to play discs but find it hates fingerprints and waking the controller is a pain, also I have that input set to game mode so not ideal for blurays/missus.

Please help

 

[gibbsy]

You could try a new high speed HDMI cable. Sometimes it can be as simple as that. The problem though, if not with a cable, is more likely the player and not the Denon as your thread title suggests.

 

[Garp]

Thanks for the reply, I have tried another hi-speed cable but doesn't seem to make any difference. Im hoping its the player and not my brand new amp as I don't want that to have to get fixed just yet. In regards to your comment about the thread suggestion, I wasn't really sure what is the problem as it was fine with my old amp and once reseted worked fine direct to the TV in bedroom. Hence Denon 4500 no blu ray sound. Thats exactly whats happening. The other connection are ok. Plus the weird auto switching has only started since having the Denon.

I may try a 3rd cable though just in case