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Audio return channel or optical audio for Dolby Digital sound?

by Santiago Barriocanal
(Asuncion, Paraguay)

I have my blu-ray player connected to the TV with an HDMI cable, and the receiver is connected to the TV. Thanks to the ARC I can hear thru the receiver what I watch on the blu-ray player. I was watching a DVD (with the blu-ray player) the other day whose audio was in Dolby 2.0, however the receiver won't show that the signal is Dolby.

However if I connect the blu-ray player with an optical (digital-in) cable, the receiver detects that the sound is Dolby, but the sound is not as loud as it is with the ARC (which won't detect that the sound is dolby).

It's a mess, but I hope it's somehow understandable. I would like to know why is that please and which way is better for instance when I have a 5.1 movie, should I use the optical or the ARC function?



Hi

Firstly, the ARC (audio return channel) function is really meant to be used for sending audio back to your receiver from devices which cannot easily be connected directly to the receiver. For example, for the TVs built-in digital (or analog) tuner that receives broadcast TV via an aerial (or antenna).

Therefore, if you have a Blu-ray player, you would usually be better connecting it directly to the AV receiver. Something like this:

Diagram of AV receiver connections with 5.1 surround sound system


This allows the receiver to do what it is best at - decoding the different types of audio signals and sending them to the speaker system.

Your TV is unlikely to have full decoding capabilities like your receiver, and so it is not surprising it isn't handling the Dolby Digital signal very well. I would guess that the TV will just be converting the Dolby Digital signal to stereo PCM and sending this to the receiver via ARC.

It's not clear from your question if you are getting surround sound audio formats from the Blu-ray when using ARC. Is the problem you are having just with stereo Dolby Digital?

The ARC feature should be capable of passing through a Dolby Digital signal, but it doesn't surprise me if you are having problems when connecting your devices this way. It may be that the TV will only pass through Dolby Digital from the internal tuner - and not from external devices connected to the TV (like your Blu-ray player).

If you want to be sure on the capabilities of your TV, check the manual, or call the manufacturers helpdesk. Also, make sure the firmware of the TV is up-to-date as there may be issues with the ARC which have been identified and fixed since you bought the TV.

However, in your case, I would just connect the Blu-ray player directly to the receiver and then you will be able to hear the best audio available. An HDMI connection would be the best type to use, however if your AV receiver doesn't have HDMI then the optical connection will be fine.

Hope that helps.

Paul (Site Editor)

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