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Optical digital out

Discussion in 'FOXSAT-HDR Freesat Recorder' started by Tony B, Jan 31, 2011.

  1. I have set up my Humax to output audio via the optical port, to my Denon amp.

    However the Denon only ever gets a 2 channel analogue feed, even though it is configured to accept digital signals on this port.

    Is there an obscure config setting somewhere in the Humax menus that I need to correct?

    Tony B
  2. gomezz

    gomezz Well-Known Member

    There are only a limited number of programmes on BBC1 HD and BBC HD which have DD5.1 audio. Everything else your amp should be able to decode into Dolby Pro-Logic.
  3. grahamlthompson

    grahamlthompson Well-Known Member

    It's not an analogue feed (S/Pdif can't carry analogue sound), for SD channels it's digital lpcm stereo decoded from mpeg1 layer 2 audio. For BBC-HD, BBC1-HD or ITV1-HD London it's either Dolby Digital 2.0 (stereo) or 5.1. ITV1-HD Granada is lpcm like the SD channels. As Gomezz says lpcm and DD2.0 normally have prologic 11 surround sound.

    My Denon amp comes up with prologic 11 for stereo transmissions but if you look closely the DD icon is lit for DD2.0.
  4. gomezz

    gomezz Well-Known Member

    I have a Denon AV amp too. Last year the BBC were flagging some DD2.0 audio as DD5.1 which sounded very peculiar (eg Springwatch). I had to switch to using the analogue audio to force it to DPL which was easy to do as I just turned off the powered optical / co-ax converter I use as my amp only has one co-ax input and one optical input (connected to the Blu-ray player).
  5. Thanks, both, for the clarification.

    Yes - I suppose S/Pdif does carry a hint that it might be digital only!

    The Denon DD indicator is just a bit small to read, without a magnifying glass (I must be getting old).

    As the transmission technology is capable of 5.1 sound, what is the BBC's excuse for using it so infrequently? I can not recall seeing the 5.1 icons light up.
  6. grahamlthompson

    grahamlthompson Well-Known Member

    The BBC-HD preview loop is in 5.1, the BBC-HD prog intro is 5.1. A few programmes are, DR Who A Christmas Carol, The Human Planet is, the main Strictly Come Dancing was. There is a test card on the BBC-HD preview loop that has a 5.1 channel audio test.

    There's a short clip here


    If you download and use AV2HDR to create the three .ts, .nts and .hmt files on a usb stick you can playback from usb and check your amp is switching to 5.1
  7. gomezz

    gomezz Well-Known Member

    It may be encouraging to note that since Christmas that around half of what I watch from the BBC HD channels is now in DD5.1 compared to around 10% before Christmas. Legacy programmes on BBC1 HD will always be DD2.0 but a lot of the newer films are broadcast as DD5.1 as well as a lot of new programmes such as Bruce Parry's Arctic. Don't expect F1 coverage to be in DD5.1 though as apparently is is tricky to balance the sound in that fast moving environment without confusing the viewer.

    BTW I have yet to see any programme on ITV1 HD which has DD5.1 audio.
  8. Well, I am now going to have to hang my head in shame....

    Yes - the BBC HD preview is indeed showing up as DD 5.1. Just goes to show how often I fire up the amp for the preview.

    It also shows massive audio lag - must be close to a second behind the video. I can adjust audio delay onthe Humax, and on the amp, but what I need is video delay!
  9. grahamlthompson

    grahamlthompson Well-Known Member

    I have 0ms on both hdr and Denon 4306 amp. Have you by any chance got a LG TV ?

    Can you confirm that the TV is connected to the hdr by hdmi.
  10. The TV is a 4 month old Samsung C8000, and the connection is via HDMI from Humax to Tv
  11. grahamlthompson

    grahamlthompson Well-Known Member

    Reason I asked was that there is a known problem with lip synch with some LG TV's and DD5.1 from seperate stb's including the hdr. Not heard of any probs with Samsungs though. It seems odd that that the TV delivers 1080i video before the amp outputs 5.1 audio. Some TV's will output 5.1 input on hdmi to their own s/pdif output. If the Samsung is one then you could try using that. Incidentally there is a 5.1 audio synch test in addition to the test card on the BBC-HD preview loop. Are you sure you have no audio delay set on either the hdr output or the appropriate input on the Denon amp ? (Mine's smack on with a W series Sony TV and the Denon 4806 with no delays)
  12. I am practically certain that no delays are set up anywhere but will check again this evening. I had thought about using the TVs optical out port but assumed that could only slow down the passage of audio to the amp, even further.

    I will give that a try too, just for comparison