Random audio loss on Sky+HD distribution

andy_48

Active Member
I have a fairly complicated and probably now 'old school' distribution system. In the attached diagram I've tried to demonstrate part of the basic setup.

The Triax 103T Modulator is a fine piece of kit but it won't distribute Dolby sound. Therefore, in order to retain Dolby locally at the AVR (Sky sound > HDMI > Dollby D) , I've taken the audio out via an optical Toslink cable (Sky sound > Optical > Normal) and the picture out via an HDMI/DVI cable (i.e. picture only, no audio) and then combined them with the Monoprice 105369 DVI & S/PDIF Audio to HDMI Converter.

My problem is loss of audio on remote TVs (all of them at the same time) on what seems to be a random basis. It is easily 'fixed' by rebooting the Monoprice box or changing the Sky box settings Sky sound > Optical > Dolby D (which makes a nasty noise) and back to Normal. However, SWMBO is inclined to express adverse comments in frustration!

I've changed all the cables but the problem persists. Short of changing the rest of the hardware (expensive and not simple), can anyone suggest what might be the route of the problem, please?
 

Attachments

  • Sky+ Distribution.jpg
    Sky+ Distribution.jpg
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Rodders53

Distinguished Member
Root of the problem is the Monoprice box doing the S-V bitstream multiplexing locking up for some reason or another.

Could be data errors in the stream from the $ky box,
could be buffer overflows within the device,
could be something to do with cross-interference within cables around the kit (though you've changed some),
could be power supply instabilities,
could be one device sitting on top of / too close to another etc.,..

What seems to be random may not be?
You need to note what programme was last working and what is on when sound is lost.
It might be related?
e.g. if it only occurs when SD channel is changed for a HD 5.1 channel or similar.
Does it only happen when an IR remote from another room is in use for controlling the box?
etc.,.
 

andy_48

Active Member
Golly, thanks! Thinking through your many suggestions I'd start with "occurs when SD channel is changed for a HD 5.1 channel or similar". My wife records and watches a lot of old SD programmes. Do you think swapping out the Monoprice box might solve the problem? Unfortunately they aren't sold in Europe (that I can find) and are therefore quite expensive and difficult to acquire. Is there a more accessible way to combine DVI/SPDIF to HDMI?
 

Rodders53

Distinguished Member
I'm no expert and not a $ky user by my 2d thoughts:

Can the $ky hdmi out be set to Stereo and the optical to Dolby (rather than Hdmi=Dolby and Optical=Stereo as you have now)? T

If 'yes' then use hdmi splitter to feed AVR and DVB-T modulator with stereo, but on AVR select an optical input when using the $ky source?

his thread suggest yes but the OP was having problems...
 

andy_48

Active Member
Can the $ky hdmi out be set to Stereo and the optical to Dolby (rather than Hdmi=Dolby and Optical=Stereo as you have now)? T

If 'yes' then use hdmi splitter to feed AVR and DVB-T modulator with stereo, but on AVR select an optical input when using the $ky source?
Thanks. Yes that's an interesting idea and would probably work. However, I'd prefer to keep the current config because I have 2 Sky boxes in different rooms each with an identical distribution setup and I'd like to keep them the same. The second one works perfectly all the time. Also, at the risk of patronising, The Boss already finds the setup complicated enough!
 

Rodders53

Distinguished Member
I have 2 Sky boxes in different rooms each with an identical distribution setup and I'd like to keep them the same. The second one works perfectly all the time.
Then it's swap components time (in a logical, controlled manner) to see if the fault follows anything... and monitor what seems to 'cause' the lockups.

But if 2 AVRs and two $ky and two modulators in the home it must be worth considering?

1. No need for the DVI device(s) and associated power supply/energy use
2. possibly no need for the hdmi splitter and psus either: use the hdmi loop-through feature of the modulator (i.e. $ky->Triax->AVR).

That removes two bits of electronics that might go wrong and / or mess with levels, noise and interference?

Assuming, of course, that the Stereo/Dolby swap works.
 

andy_48

Active Member
Then it's swap components time (in a logical, controlled manner) to see if the fault follows anything... and monitor what seems to 'cause' the lockups.

But if 2 AVRs and two $ky and two modulators in the home it must be worth considering?
OK thanks. I'll give it a shot. It's going to be a rainy day tomorrow......
 

andy_48

Active Member
Root of the problem is the Monoprice box doing the S-V bitstream multiplexing locking up for some reason or another.

could be power supply instabilities,
The power supply that I have been using to the 'dodgy' Monoprice DVI device was the original 2-pin block supplied from the USA plugged into a 3-pin shaving adapter. I'd forgotten this was the case and wouldn't have thought it might be a problem! I've swapped it for a 'normal' 3-pin power block that I managed to find (5 volt, 2 amp, 3.5mm jack plug - not 'normal' at all in the UK!) and it seems to have cured the problem.

Many thanks for all your help and advice. Massively appreciated.
Andy
 

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