The Audio Return Channel in HDMI 1.4 enables a TV, via a single HDMI cable, to send audio data “upstream” to an A/V receiver or surround audio controller, increasing user flexibility and eliminating the need for any separate S/PDIF audio connection.
TVs have always been able to receive multi-channel audio through an HDMI connection, and this is still a typical use-case, with the TV positioned “downstream” from content sources and any connected audio equipment. However, if a user had a TV with a built-in tuner or DVD player, and wanted to send content “upstream” from the TV back to the audio system, a separate connection had to be installed, typically an S/PDIF cable.
An ARC-enabled TV can either send or receive audio via HDMI, upstream or downstream, depending on system set-up and user preferences.
LipSync functionality, introduced in HDMI 1.3, ensures that the audio stays matched to the video, automatically compensating for any processor delays whether the audio is traveling upstream or downstream.
In theory, ARC is supposed to let you have one connection between your TV and whatever you use to create sound: a receiver or a sound bar. You send video to the TV with an HDMI cable, and that same HDMI cable sends audio from the TV back down the same cable.
This is great for smart TVs, where the TV itself is creating the audio (via apps like Netflix and Pandora). Instead of suffering through a TV’s terrible speakers, the audio gets sent to the receiver/sound bar for a massive improvement in sound quality.
Another way this is great is if you have multiple sources (Blu-ray, cable box, Roku), but only one input on your sound bar. With ARC, you can connect everything to the TV, and the TV will send audio down an HDMI cable to the sound bar. No extra cables needed (i.e. an optical cable).
Audio Return Channel is convenient and can simplify your setup. However, it might also mean you don’t get surround sound, and it definitely means you won’t get the high-resolution audio formats from Blu-ray.
So for the best sound quality, it’s still recommended to use individual HDMI cables to link to a sound bar or receiver when you can.
To check ARC functionality, one can:
- Look for devices that feature Audio Return Channel functionality.
- All HDMI cables will support Audio Return Channel functionality when connected to Audio Return Channel-enabled devices. You can use your existing HDMI cables or choose a different cable type.
- Connect your devices through Audio Return Channel-enabled HDMI ports. HDMI Licensing has strongly recommended that Adopters label all Audio Return Channel-compliant HDMI ports with the letters “ARC” for easy identification, but does not require manufacturers to do so. Please check with your manufacturer to determine which HDMI ports (if any) will support Audio Return Channel functionality.