Audio

Dolby Digital Plus

DD+, the streaming and ARC workhorse

DD+ is the format most streaming soundtracks actually arrive in, and the best that an ARC connection can carry. On the Diva it decides how sound gets from a TV app back to your AVR.

Dolby Digital Plus, usually written DD+ and known in the specifications as Enhanced AC-3, is the successor to the Dolby Digital found on DVD. It appeared with the high definition disc formats around 2005 and went on to become the standard soundtrack of streaming, running at bitrates several times higher than Dolby Digital's 640kbps and supporting up to 7.1 channels. It is a lossy codec: unlike TrueHD it does not reconstruct the studio master bit for bit.

Its second life is Atmos. Dolby Atmos object metadata can travel inside a DD+ stream as an additional layer, which a decoder that does not understand it ignores harmlessly. That is how streaming services deliver Atmos, and it is why DD+ matters so much on a return path from a television: ARC has room for DD+ and therefore for Atmos over DD+, but not for the lossless TrueHD carriage used on disc.

Dolby Digital Plus on the HDfury Diva

The Diva performs no audio format manipulation. What comes in goes out untouched, so DD+ arriving at an input reaches TX0, TX1 and the dedicated HDMI audio output as DD+, and whether your AVR receives it depends on the EDID the Diva presents to that source rather than on any conversion in the box. Lossless formats travel by HDMI only; the optical output carries up to 5.1 and the analog side is stereo.

The interesting direction is the other one. From a television connected to TX0, the Diva handles up to DD+ and Atmos over DD+ bitstream over ARC, and you can route that to the dedicated HDMI audio output, to the optical output, or to both. Three settings in the CEC and RS232 section make it work: ENABLE CEC ticked, the CEC device type set to Audio Processor instead of the default Video Processor, and Enable DD+/ATMOS ARC ticked. Over IP those are set cec on, set cecla audio and set archbr on, and ARC HBR in the OLED menu is the same switch.

Where to send it

Very few AVRs accept 192kHz audio on an optical input, so in most setups DD+ and Atmos pulled from a television should go to an HDMI input on the AVR through the dedicated audio output, not to the optical jack. If ARC audio never appears at all, the CEC device type is the first thing to check: with Video Processor selected, the Diva is deliberately leaving ARC to your AVR.

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