Audio

ARC

Audio Return Channel

ARC exists so that a television can send its own sound to an amplifier over the HDMI cable already joining them. On the Diva it works from TX0, it depends on CEC, and one setting decides whether it happens at all.

ARC stands for Audio Return Channel and arrived with HDMI 1.4 in 2009. It repurposes a pin in the connector to carry an audio stream upstream, from the television back to the device connected to its ARC labelled port. Before it existed, a separate optical cable was the only way to get the sound of a television's own tuner or apps into an amplifier.

The channel is roughly the capacity of an optical link, so it carries stereo PCM, Dolby Digital and DTS 5.1, and, where both ends implement it, Dolby Digital Plus including Atmos over DD+. Lossless formats are outside its rate. Setting it up is not automatic either: ARC is negotiated over CEC, so the two ends have to agree over the CEC bus about which device is the audio system before any sound flows.

ARC on the HDfury Diva

CEC and ARC master is TX0. The television you want audio from belongs on the TX0 output whatever you consider your primary display, and TX1 stays free for a second, older screen. From there the Diva handles up to DD+ and Atmos over DD+ bitstream, and you can route that sound to the dedicated HDMI audio output, to the optical output, or to both.

The settings are in the CEC/RS232 section. ENABLE CEC has to be checked before any dropdown below it is applied to the unit. The device type below that is the one that catches people out, because it decides who owns ARC in your setup. Enable DD+/ATMOS ARC then extends what the Diva will pull back from the television. The same three appear over control as set cec, set cecla and set archbr, and in the OLED menu as CEC, CEC LA and ARC HBR.

Video Processor

The default. Choose it when an AVR in your setup should be the device using ARC or CEC, and the Diva stays out of the way.

Audio Processor

Choose it when you want the Diva ARC feature on, so sound from the television comes back into the unit and out again on the HDMI audio output, the 5.1 optical output or the analogue stereo jack.

When no sound comes back

Check the device type first: if ARC audio never appears, that setting is the usual cause. Then check the cable, because Atmos over ARC requires an HDMI cable that supports 192kHz ARC, and a cable can carry a 600MHz video signal perfectly and still fail on the audio one. Finally check where you have connected the AVR. Very few AVRs accept 192kHz over optical, so in most setups DD+ and Atmos should be fed to an HDMI input on the AVR from the dedicated audio output rather than down the optical jack.

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