Technology

HDMI ARC : How does it work?

Audioquest Cinnamon HDMI

The audio return channel (ARC) offered by HDMI 1.4 or HDMI 2.0 controllers on recent audio-video devices (televisionshome cinema receivers or soundbars) allows a compatible receiver to receive the sound coming from the TV via a single HDMI cable. In other words, the HDMI cable used to send the image and sound from the receiver to the TV also works the other way around. Sound can thus be sent from the television to the receiver or soundbar.

A double configuration is necessary

A few adjustments are necessary for the ARC to work. Simply connecting the TV to a home cinema receiver (or soundbar) is not enough for the former to send sound to the latter via the HDMI cable.

In order to make the HDMI ARC connection between the TV and receiver work, it is necessary to activate both the ARC option and CEC protocol in the television and receiver’s menu, one after the other. The receiver or soundbar needs to stay on while setting up the television.

It is necessary to activate the Consumer Electronic Control (CEC) for the Audio Return Channel (ARC) to work properly. The HDMI CEC technology enables various HDMI devices to communicate between each other which results in the possibility of operating them via a single remote control (that of a television, home cinema receiver, soundbar, Blu-ray player or set-top-box for example).

Note that CEC technology has been renamed by some manufacturers. It is called Viera Link by Panasonic, Bravia Theater Sync by Sony, AnyNet+ by Samsung, Regza link by Toshiba, Aquos Link by Sharp… A quick look at a device’s user guide will, of course, provide a better understanding of the menu.

Be careful: it is necessary to deactivate the integrated speakers for certain televisions in order to benefit from the ARC. It is recommended to deactivate the integrated speakers in the TV menu after activating the CEC and ARC protocols.

The receiver controlled by the TV

Once configuration has been properly carried out, switching on the television will automatically activate the receiver and select the ARC mode. Better yet, the volume function of the TV remote control can be used to adjust the receiver’s sound level, there is therefore no need for the receiver’s remote control anymore. Once the TV is switched off, the receiver will automatically follow suit. This is the main advantage of the CEC protocol.

Which port should you use to connect the HDMI cable?

An HDTV often features several HDMI inputs. Not all HDMI ports are ARC compatible. Most of the time, only one HDMI port is ARC compatible and will be labelled as such. The same rule applies to home cinema receiver equipped with several HDMI outputs, only one will be ARC compatible. The ARC compatible port of a soundbar or receiver is always indicated.

Back panel of the Denon AVR-X3000

For receivers featuring several HDMI ports, the ARC compatible output is also labelled.

What are the compatible sources?

It depends on the television. Most TVs can redirect any incoming digital audio stream to the receiver via its HDMI inputs. With the ARC, a home cinema receiver can thus deliver sound from a Blu-ray player or multimedia player connected to the television. The early models of TV featuring an HDMI 1.4 port, released in 2011, were sometimes only capable of directing sound coming from the DTV to the ARC. Televisions released after 2013-2014 are, on the other hand, not limited.

Is the audio quality inferior to that of a direct connection?

The audio stream transmitted to the receiver via the ARC is identical to the original, there is therefore no degradation of the signal. Yet, if you activate the conversion to PCM stereo format in the TV menu, the DTV’s Dolby Digital or DTS stream coming from a Blu-ray player will be converted from 7.1/5.1 to stereo format. This conversion function can be useful for certain soundbars if they are not compatible with Dolby Digital (used by many channels) or DTS (often used for Blu-ray discs).

Be sure not to activate this conversion if you want your home cinema receiver to receive the original DTS or Dolby stream.

Logo DTS HD Master Audio

DTS HD Master Audio stream can be transmitted from the TV to the receiver without any alteration

Is it necessary to use a certified cable?

It is always the best option, but HDMI 1.3 cables are perfectly compatible with the ARC. In practice, the structure of the cable is the same, the ARC compatibility comes from the home cinema receiver and TV controllers. A standard HDMI cable is enough to enjoy the possibilities offered by the ARC. Nevertheless, we warmly recommend using quality HDMI cables, particularly for long distances, in order to avoid any possible transmission error which will impact the sound, especially in the higher end of the sound spectrum. HDMI 2.0 certified cables are also compatible. Visit our wide selection of ARC compatible HDMI cables.

This post was originally written in 2011. The arrival of devices featuring ARC compatible HDMI 2.0 ports required a content update. We also do our best to answer all questions and comment as often as possible and in a timely manner.

This post is also available in: French

About the author

Tristan Jacquel

Tristan est rédacteur chez Son-Vidéo.com. Passionné de musique, d'acoustique et de high-tech, il réalise notamment les tests matériels pour notre blog.

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