Originally Posted by ane _81
Hi, I have really strange issue with ARC.
Recently I bought LG OLED C9 together with Marantz SR5013 receiver. I wasn't able to set ARC working with LG and I my overall experience with Marantz was bad (bluetooth, bad options, lack of settings, bad display...)...it just wasn't built for home cinema.
I returned Marantz mostly due to ARC incompatibility with LG and gave a chance to new Onkyo TX-NR696.
And it worked flawlessly and I'm more then happy with Onkyo, Everything works perfect and sounds amazing.
But there is one strange issue that just makes no sense. ARC is working but only under certain conditions and I don't know whom should I blame, Onkyo or LG. ARC is working only if I have one HDMI cable connected, the main one that goes from Onkyo HDMI ARC port (out) to LG HDMI 2 port (ARC). If I connect one additional HDMI cable to AV receiver, for example PS4 HDMI to GAME port of the AV receiver, ARC immediately stops working and TV switches sound from the 5.1 speakers to TV speakers. When I plug out the HDMI cable from GAME port after few seconds ARC begins to function and sound comes out from 5.1 speakers.
To make it more complicated, if I plug directly HDMI cable from PS4 to TV HDMI1 port (so not to go via AV receiver) the same thing happens and ARC stops working so this must be due to LG and not due to Onkyo, right?
This is strange and I cant' find logic behind this. Where's the catch and is there something that I could try? Currently I'm using 1.4 HDMI cables. I also tried with 2.0 cable (cheap model) and the problem was the same.
First of all, there is no such thing as an HDMI 2.0 cable, or even 1.4. The current HDMI passive cables are labeled as Premium High Speed HDMI cables and should come with a QR label for authenticity. HDMI.org asked cable mfrs years ago to not label their cables with the HDMI specification number and to just use High Speed HDMI or Premium High Speed if the cable has been tested by an HDMI.org approved certification program. This is for passive copper-only cables up to the maximum certifiable length of 25'.
As a test, I'd disable ARC/CEC on all your connected devices to make sure that they work as expected. It could be a CEC incompatibility that can sometimes affect ARC. The issue is not specific to LG, Onkyo, or any mfr for that matter. CEC is not standardized in the sense that all mfrs have to follow the same protocols so the implementation of CEC is up to the various mfrs, which may lead to incompatibilities. Some newer devices allow the user separate control over ARC and CEC so one can enable/disable either option. Other devices may not allow this so it's either both enabled or both disabled. ARC will only work on the HDMI port that is specifically labeled for ARC.
If all you are concerned with is 5.1 audio, then you could use an optical cable from the tv to the receiver for the LG's onboard apps. You won't be losing any audio fidelity because optical and ARC both deliver 5.1. To use ARC, you should be keeping the LG's speakers off.
There are no firmware upgrades that can correct a CEC incompatibility, so if you do determine that it is a CEC issue and you need ARC, you can use the Lindy CECless adapter which disables the pin 13 responsible for CEC which will still allow you to still use ARC.