What is HDMI eARC? Enhanced audio return channel explained

Want the best quality and least hassle when connecting your TV to a soundbar? HDMI ARC and eARC are your friends

surround sound control
(Image credit: Dennis Fischer Photography / Getty)

The audio-visual world loves an acronym, so if you've heard about HDMI ARC or eARC and have been left scratching your head as to what these mean, then worry no more as we explain through these terms' meanings and importance.

HDMI actually stands for High-Definition Multimedia Interface, but the acronym, which is also a trademark, is so commonly used that you'll probably never hear anyone blurt out the full-blown expression. 

In its simplest terms: HDMI is used to transmit uncompressed video and audio data between devices, such as between the best TVs and a Blu-ray player, games console, soundbar, and so forth.

What is ARC?

Samsung Q900R

(Image credit: Samsung)

HDMI has evolved over the years, with HDMI 1.4 bringing ARC, or Audio Return Channel, into the mix back in 2009. It's remained in every specification ever since then.

ARC enables your TV or audio system to communicate signals in both directions, not just one, by 'hand-shaking' and synching control between two devices. It means the end of multiple cable connections of old, seeing one HDMI cable to rule all. 

ARC is especially useful when pairing one of the best soundbars to a TV, for example, as you can adjust the volume of your TV and that will sync with the soundbar setup automatically. No need for multiple volume controllers for the two different products – simply use your TV remote.

However, most TVs only feature one solitary HDMI port marked with 'ARC', so you'll need to ensure you use that port to connect devices with an HDMI cable, otherwise it won't work properly.

What about eARC?

Samsung HW-Q990B soundbar

(Image credit: Samsung)

A decade after ARC launched, the HDMI 2.1 specification arrived, including eARC, which stands for Enhanced Audio Return Channel.

The 'enhanced' part of the acronym is the key point here: eARC can handle higher bandwidth sound formats, meaning up to 32 channels of audio at up to 24-bit 192kHz can be sent uncompressed.

Why does that matter? Well, not only is there the potential for better audio quality, such as Dolby TrueHD and DTS-HD Master Audio, it means the HDMI cable can handshake with object-based sound formats, such as Dolby Atmos and DTS:X. 

With surround sound easier to obtain than ever before, and such mixes supported by the best streaming services for many shows, if you've got the right soundbar kit then eARC is an essential to get the most from it.

And HDMI 2.1?

HDMI

(Image credit: Future)

It's not just eARC that came as part of the HDMI 2.1 package though, which, at the time of writing is the most current format. 

HDMI 2.1 is important for new-gen gaming – if you're using PlayStation 5 or Xbox Series X – because it supports 4K resolution at up to 120Hz for the smoothest refresh rates, including compatibility with variable refresh rate (VRR) and auto low-latency mode (ALLM). 

There's even more future-proofing in HDMI 2.1, too, as it supports 8K resolution up to 60Hz. The previous HDMI 2.0 only supported half that frame rate: 4K at 60fps and 8K at 30fps, so the seemingly small '0.1' is a big jump forward. 

In 2022 the HDMI Forum also released version 2.1a of the HDMI specification, which includes Source-Based Tone Mapping (SBTM) to allow a source device to control high dynamic range (HDR) mapping instead of the display device. 

Mike Lowe
Tech Editor

Mike has been writing about consumer technology for 15 years and is T3's Tech Editor. As a phones expert he's seen hundreds of handsets over the years – swathes of Android devices, a smattering of iPhones, and a batch of Windows Phone products (remember those?). But that's not all, as a tech aficionado his beat for T3 also covers tablets, laptops, gaming, home cinema, TVs, speakers and more – there's barely a stone unturned that he's not had a hand on. Previously the Reviews Editor at Pocket-lint for a full decade, he's also provided work for publications such as Wired, The Guardian, Metro, and more. In addition to his tech knowledge, Mike is also a flights and travel expert, having travelled the globe extensively. You'll likely find him setting up a new mobile phone, critiquing the next MacBook, all while planning his next getaway... or cycling somewhere.