If you’re the owner of a newer HDTV, A/V receiver, sound bar, or home theater in a box (HTIB), you may have noticed (then promptly forgotten) a little symbol on one of the device’s HDMI inputs that says “ARC.” What does this mean? Hint: it has nothing to do with the reactor that powers Ironman’s suits.
ARC stands for Audio Return Channel, which is a little-understood protocol that started showing up on HDMI-equipped devices a few years back. Today, it is increasingly common. The technology is especially useful and has the potential to significantly simplify home entertainment systems. Unfortunately, few know it even exists, much less what it can do. Here, we’ll go over the basics of ARC so you can put its mythical powers to work for you.
But first, a quick refresher on HDMI itself (feel free to skip ahead if you just need to know how ARC works).
HDMI: The basics
HDMI, which stands for High Definition Multimedia Interface just celebrated its 10th birthday this month. You probably use it now, but you may not know how cool it actually is. The system was created as a faster, more efficient way to deliver high quality digital video and audio to and from consumer electronic devices. The interface’s current iteration is HDMI 2.0b, a baby step above HDMI 2.0a which now allows for transmission of 4K Ultra HD video with HDR at up to 60 frames per second, as well as the ability to transmit up to 32 channels of audio. A constantly evolving format, HDMI 2.1 set to push the format even further, allowing for transmission of 8K resolution at up to 60 frames per second and 4K content at up to 120 frames per second, equating to faster and more efficient transmission to keep up with the monster file sizes of our video and audio future.
Like previous iterations, the current HDMI 2.0b format is compatible with all older hardware, but the nature of high resolution content means you may need to purchase high-speed HDMI cables for best results.
Though many people use HDMI strictly as a means for connecting cable boxes, Blu-ray players, and game consoles to their TV, it can do much more.
Besides transferring both video and audio in a single feed, HDMI was also designed to carry what the industry refers to as “handshake” information from one device to another. These shared transmissions were originally intended to communicate basic data for preventing content theft, as well as messages like the status and type of component connected.
But the system was also designed to share more complex messages as a part of what’s called Consumer Electronics Control (CEC). CEC allows for a single remote to control features on up to 15 connected devices. There are virtually as many names for CEC as there are electronics brands: Samsung calls it “Anynet +,” for instance. Unfortunately, the system has never really lived up to its potential, and is often mistranslated or simply lost between components from different manufacturers. Until ARC.
The power of ARC
ARC can simplify your home theater system in two important ways. The first, and perhaps most useful feature ARC brings to the table is the ability to use one remote for all of your connected devices’ most common functions.
The most common example would be for users who have added a soundbar, HTIB, or other secondary audio device to their TV. As long as both devices are equipped with ARC, simply connecting the HDMI cable to both devices’ ARC HDMI port will allow for control of power, volume, and other features from your TV remote. In some cases, it will also simply transfer your TV audio to the unit automatically without having to deactivate the TV’s on-board speakers.
This feature is extremely useful for those who connect gaming consoles, Blu-ray players, set-top boxes, and other devices directly to the TV rather than an audio receiver. It allows for significantly better audio performance for all of your content than what you’ll get from a TV alone, but without having to think about the audio device.
Alternatively, ARC is also handy for other outboard components like streaming devices. Plugging the Chromecast into your TV’s ARC port, for instance, may allow you to automatically switch sources or even turn on your TV when you click the cast icon on your phone or tablet. You may find similar results with other components as well, including Blu-ray players.
In through the out door
The other important function ARC performs is sending signals both “upstream” and “downstream” over a single connection, meaning signals can travel in and out of a device over a single ARC HDMI port and cable. “Downstream” refers to signal that is being passed from the source, say a Blu-ray player, “down” to another device. “Upstream” would then mean sending signal the opposite way over the same cable. Why is that necessary? Convenience.
For those who use an Audio/Video receiver (or a soundbar with multiple HDMI inputs) as a hub instead of their TV, ARC can still simplify cable connections a little. While audio and video from various sources is going directly to an A/V receiver in this kind of setup, any audio coming from the TV still needs to get to the receiver somehow. For instance, let’s say that the television is the preferred smart device in the bunch. Any audio from Netflix, Hulu plus, etc., will only play out of the TV if it is sent to the receiver somehow. In the past, this would have required another cable, usually an optical digital cable. But with HDMI ARC, audio can be sent back down to the receiver through the same cable that already connects the two devices. For those with wall-mounted TVs, that’s one less cable to snake through the wall!
Another important point to consider is that the above method of connection is preferable for those who want to utilize the full sound capabilities of DTS and Dolby surround sound from Blu-ray, DVD, and gaming content. In many cases, connecting a component to the TV directly will reduce the signal to two-channel audio, and it may also reduce the sound resolution. Routing the audio signal through the receiver instead will preserve the original, high-definition audio signal, ensuring you get the best possible experience.
Let’s say you don’t have an A/V receiver, though. Some high-end soundbars also include multiple HDMI inputs to allow a direct connection from a Blu-ray player or other source, allowing you to preserve the audio quality. Again, you can connect the bar to the TV via the ARC HDMI connection to pass the video signal to the TV, and also to receive audio back from TV programming, or other components connected to the TV. If preserving the full-scale audio signal is important to you, you’ll want to do some due diligence about the available audio connections before you decide on a soundbar or other supplemental audio device.
What do I need to activate ARC?
All you need for ARC to work its magic is to make sure any connected components are equipped with ARC, and then simply connect them with a recently-made HDMI cable (2009 or later) . If your current HDMI cables are ancient it won’t cost you more than a few dollars to upgrade. In some rare cases you will also need to go into your components’ settings to activate ARC, but the vast majority of devices have it enabled by default, making it a plug and play affair.
Bam! Now you know more about ARC than almost everybody you hang-out with. Share the love!
Updated 1/23/2017: Added information about HDMI’s latest iteration and hardware specifications.