Sky HDMI and Dolby Digital (5.1)

At the weekend, I was in a local branch of a national chain that sells high end home entertainment equipment, having a nose to see what’s new. Whilst I was in there, a member of public came in and asked a member of staff “how can I hear sound through my TV without having to have the AV Receiver on?”. The answer, “just turn down your receiver…”. Really?


I guess that’ll work to an extent, depending on set up, but an interesting line of advice from a specialist store that focuses on high end home entertainment equipment. He did later go on to start offering better advice after the customer challenged, but at the same time, I didn’t want to hang around like a bad smell.

However, all is not straightforward when it comes to setting up Sky to run through a receiver, as Sky boxes only output stereo over HDMI, not full 5.1 Dolby Digital (depending on channel and broadcast). Don’t ask us why, they just do, but this makes things slightly more complicated than it should be if you’re looking to go for 5.1 Dolby Digital, rather than just 2 channel stereo. To achieve Dolby Digital, you need to use the digital output of either optical or coaxial from the Sky box to your receiver.

There are therefore a couple of solutions depending on how you’d like it controlled.

1. HDMI direct to TV, with digital out into the receiver (TV & receiver controlled independently)

2. HDMI and digital out both into receiver (Receiver controls audio and visual)

With option 1, you can have just the TV on and have sound and picture like normal. But at the same time, if you want the improved sound, fire up the receiver and select the audio input that Sky is connected to and appreciate the improved sound.

With option 2, things are slightly more complicated to set up, but may end up being easier to use. In this instance, both HDMI and audio will connect to the receiver and whatever source you select on the receiver (Sky, Freeview, XBox, Playstation etc), that is what you’ll see on the TV and hear through the speakers.
Depending on receiver, you may have to assign an audio input to match the HDMI input. For Sky, as picture comes through HDMI and Dolby Digital audio through digital, the two sources need to be paired as one. Then when the HDMI selection of Sky is made on the receiver, the assigned audio input will also be selected and you’ll get both picture and Dolby Digital sound through the receiver. Most other sources such as XBox, Playstation etc output Dolby Digital over HDMI, so just the single HDMI connection to deal with. The end result is, whatever you select on the receiver comes out of the speakers and is displayed on the TV at the same time.
But, and there’s always a but, depending on the receiver being used, you may not be able to use just the TV for visual and audio, as some receivers don’t have HDMI pass through. What does that mean? Basically, when the receiver is switched off, no signals are passed through the receiver. So if you’ve Sky HDMI -> Receiver -> TV HDMI, then no picture of sound will appear on the TV. Most receivers now have HDMI pass through, which means, even when switched off the signals are still passed through the receiver so it doesn’t need to be on if you only want to use the TV for picture and sound. So worth keeping in mind when looking for a receiver.

We hope that all made sense, but if you need any help, impartial advice, or want help with your own set up, feel free to get in contact as we’ve years of experience in home cinema.

UPDATE (01/05/2013) – Sky are finally rolling out an update to allow Dolby Digital over HDMI! Read about this feature and what else is coming in the update here.

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