What is HDMI ARC and HDMI eARC?

hdmi ARC

To make it very clear what is HDMI ARC I will give a personal example. In 2016 I decided to leave home theater and give soundbar a chance (I enjoyed this exchange so much that I even wrote an article about it at the time). Evidently I felt the thud of going from 5.1 channels to 2.1, from JBL SB 350, soundbard that I bought, however, for the sake of space and less cables thrown by the environment, the soundbar fell like a glove in my case.
This soundbar is connected to a 40-inch TV bought at the same time, the Samsung KU6000. Although the JBL soundbar offers both auxiliary and optical connection, the interconnection with the television was done via HDMI, thanks to support for ARC technology. We commonly associate HDMI only as a form of video transmission, but from version 1.4 of HDMI the audio feedback was introduced. ARC is an acronym that symbolizes precisely this possibility. The audio R eturn C hannel - audio return channel.

Thanks to the ARC my soundbar could be connected to the television via HDMI, and that same cable takes care of the audio transition, the sound pass, which by default would be emanated from the TV speakers to the soundbar. The image below taken from the soundbar JBL Bae 2.1 product guide illustrates this integration.

In addition to its sound system, the TV also has to offer HDMI ARC compatibility for everything to work perfectly. Rest assured, all the TVs you find on the market today will offer this possibility. The HDMI ARC was introduced in 2009, has been in the market for a long time, and all manufacturers already offer this type of solution, even in input or intermediate TVs.

At the time of connection you will have to pay attention, the HDMI port facing this audio feedback will have a prominence over the others on your TV. I will quote my case again. Samsung's KU6000 TV offers 3 HDMI ports. Port number 3 has the word ARC in parentheses, indicating that it will be specifically there that the connection to the soundbar or receiver, for example, will be made. Some manufacturers may use other ways to highlight HDMI ARC by using the term “TV ARC”. No matter how written you already know that the HDMI port that has any mention of ARC will be the one that will make the connection to your sound system.

Another advantage offered by HDMI that is in tune with ARC is that with the television control itself you adjust the volume of the soundbard, for example. The JBL SB350 has a dedicated remote control, but I turn up the volume directly through the TV control. This is possible due to another feature of HDMI, the Consumer Electronics Control (CEC) - remembering that each manufacturer adopts the trade name that they think best. Example: Samsung calls Anynet +, LG SimpLink, Sony Bravia Sync, and so on. Of course the use of the dedicated control still has its value as there are more specific functions, for the JBL SB350 the subwoofer bass adjustment is made by this control.

In addition to convenience, ARC via HDMI has also made a technical leap in specifications that is worth commenting on. Prior to HDMI ARC, RCA, with its coaxial cables, and TOSLINK, which uses fiber-optic cables, were the most common forms of this audio transfer. Even in the case of TOSLINK, which uses fiber, the difference between transmission bandwidth compared to HDMI ARC is brutal: 384 Kbps x 1 Mbps.

 Difference Between HDMI ARC and HDMI eARC

Now there's an important detail: In the ARC standard itself there are differences, there is an improved version, eARC . From HDMI 2.1, announced in 2017, ARC technology has been improved, giving rise to eARC. Just as there are considerable differences between TOSLINK and HDMI ARC bandwidth there is also a discrepancy between ARC and eARC in this regard. While ARC offers 1 Mbps bandwidth, eARC raises to 37 Mbps. But what the hell this aggressive leap for? The answer is clear in a table shared by HDMI.org, which is responsible for licensing HDMI specifications and promoting the technology.


The table shows that while ARC only handles compressed 5.1 audio, eARC can handle 5.1 uncompressed beyond 7.1. This standard can also hold the edge in modern surround sound technologies; such as Dolby Atmos or DTS: X. The eARC is suitable for those who will build a high end configuration, which will probably go through some very robust receiver. Look out for the resolution and sample rate that eARC supports: 24-bit, 192 kHz!

As with HDMI ARC, to use eARC you will need both the TV and the audio receiver to support, ie support HDMI 2.1. So far few products have met this prerequisite. The cable also needs to be sturdy, HDMI.org says you need a High-speed HDMI cable with Ethernet. It is also worth mentioning that eARC is fully ARC compliant. If you buy a new TV that supports eARC but maintains audio equipment that only handles ARC integration will occur.
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