Originally Posted by Alex Hall
So I'm running my sony 4k receiver from the arc hdmi output on the receiver to the arc hdmi input on my tv,it sends audio from the tv to my speakers fine. I also have my Xbox one x in hdmi 2 on the tv and for some reason I'm getting the xbox's audio through my receiver and to the speakers. I'm not complaining, I'm just wondering is this how arc is supposed to work? I would have no problem running my Xbox into the receiver, but I tested it and it won't display 4k. Let me know and thanks in advance! My first post on here so go easy lol
ARC sends SPDIF quality (i.e. roughly the same as an optical out or a coax out) audio the 'wrong way' down an HDMI cable. It's really designed to get a TV's tuner audio back down to the amp without having to install a second cable. It carries PCM 2.0, DD and (in some cases) DTS audio. Most high quality HDMI sources like consoles, Blu-ray players etc. will output PCM 5.1/7.1, Dolby True HD (sometimes with Atmos), DTS HD MA/HRA (and DTS:x), and Dolby Digital Plus (I believe there may be some DD+ over ARC - not sure)
Some TVs will also route audio from other inputs - HDMI sources for example - down the ARC connection. However these will be limited to the ARC's capabilities, and if you have a good quality AVR, you will be compromising your audio connectivity if you put ARC 'in the way'.
However if your AVR is a legacy HDMI 1.4b or below device and/or doesn't support HDCP 2.2 AND your source only has one HDMI output yout have to chose between high quality audio and HD video (routed through your AVR), or compromised audio quality and 4K video (routed directly to your TV with ARC audio) (some UHD Blu-ray players have two HDMI outputs for this very reason - one HDMI 1.4 output carries audio only, the other HDMI 2.0 carries both audio and video. My UBP-X800 does this for example)
There are devices that you can get that will sit between devices and strip off the HDMI audio and output it over an HDMI 1.4 connection, and pass through the video over and HDMI 2.0 connection. However they aren't cheap. (HD Fury make one)
There IS a new version of ARC coming - which supports full quality HDMI audio - but it's only going to be supported by - you guessed it - new AVRs and TVs...