No sound output from cable box going to tv, then surround sound

I have a DCI401TWC2 basic cable box and when I route the cable box to my Xbox one's HDMI in, then to my LG tv for video via HDMI out, and optical audio out from the Xbox one to a denon receiver for my surround sound system, everything works perfectly.

But when I plug in the cable box via HDMI straight to the tv I get no audio. I do get an hdcp authentication failure message which flashes a few times before the video becomes stable and the error goes away but no audio.

The tv has optical audio out to the denon surround sound but even if the tv is switched to internal speaker out or even Bluetooth speakers i still get no audio.

Since it is such a basic cable box I have no audio options in the settings except Spanish or English output so I'm at a loss for how to get this working.

I also have hooked up an external hard drive via usb to the tv directly, and was able to play video with audio via the optical audio out from the tv to the denon receiver, so i know the set up does work.

Does anyone know why it won't work with the cable box?

Re: No sound output from cable box going to tv, then surround sound

[ Edited ]

what model TV? does it have the latest firmware?

 Does it have multiple HDMI ports?

Are you trying to switch HDMI cables without turning everything off and back on?

Does your tv have an HDMI ARC/ CEC port?


What or why  are you trying to loop thru so much stuff?



Re: No sound output from cable box going to tv, then surround sound

It's a new LG 4k 70 inch tv from Costco (can't remember the model number) it has 3 HDMI ports and I've tried 2 with different cables. I don't know if it has one of the arc/cec ports and come to think of it I don't know if I tried it with every thing turned off first...

It's looped through so much because the tv is wall mounted with the cables through the wall and an entertainment unit on the ground in front of it so I have everything already in place to be used in that set up.

Essentially I just want to be able to remove the Xbox from the loop when i need to so it could be used via screen share on my laptop and my wife can watch tv and i can use the xbox at the same time