HDMI ARC Explained
What is it?
The often-overlooked ARC stands for ‘Audio Return Channel”, and ever since the HDMI 1.4 standard was introduced, ARC has been available on TV’s, soundbars and receivers. This protocol offers two-way communication between devices over a single HDMI connection.
Essentially, the HDMI ARC port lets you use HDMI as both an input and audio output.
The two way movement of sound by HDMI ARC means that you can easily do some things that used to require extra cables.
First, you can connect your audio system with a single HDMI cable. Connect your soundbar to the T.V using the designated ARC-capable port, and you can use it for every device that connects to the T.V, including Blu-ray players, game consoles and other devices, and it does that through the T.V itself, instead of requiring a separate audio receiver.
Second, you can run these connections through the soundbar itself, letting you shift the multiple HDMI connections from the T.V to the soundbar without requiring any additional setup. This is especially helpful for instance in which your T.V is wall mounted and you either don’t have access to all the HDMI ports or simply want a cleaner look with fewer cables running to and from the T.V. It also means fewer cables to install.
HDMI ARC cannot send HD or high bit rate audio used by standards like Dolby Atmos and DTS:X. This is especially problematic because downstream audio over HDMI can carry the signal with no problem; it’s purely a limitation of the ARC spec.
Even more irritating, some TVs actually downgrade the audio output over ARC, converting everything to two-channel sound even if it originated as 5.1 audio. It's not common, but depending on your make and model of TV, you might actually wind up with lower sound quality over ARC. In these instances, connecting an extra audio cable or two may be worth the trouble.