Help with frustrating HDMI sound issue please

picnic

picnic

picnic

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So I have my Sky Q HDMI out going to a manual HDMI switch, one leg goes to the TV in the front room (this works fine) the other goes via long HDMI cable to a TV in the bedroom. It's this TV in the bedroom I have a problem with. When the TV is first turned on there is picture but no sound. If I wait, after about 15 mins, the sound will come on and I'll have no problems with it until the TV is turned off.

If I disconnect the HDMI at the back of the TV and reconnect it there is instant sound.
If I plug the cable directly in to the Sky Q, taking out the switch, it works. Again instant sound when the TV is turned on.

A full power off of the TV (at the mains) doesn't help.
Changing audio formats on the Sky Q box doesn't help.
Picking 720 rather than 1080 (to reduce the bandwidth) doesn't help.

I guess this is a HDMI handshake issue but why do I have to wait 15 minutes when disconnecting the cable and reconnecting always results in the sound working.

TV is a Sharp 50FJ2K, it replaces an old LG LCD TV that worked fine until it went pop.

Any practical things I can do to fix this please?
 
Hdmi circuit can be damaged so only plug with fully unplugged mains cable on everything. Not whilst any component is on nor even on standby as still has power.

20m is too long for HDMI likely that is the cause. You may need a active HDMI cable.

If you're able to test with a short cable, and it works then it's the long HDMI cable causing problems.
 
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picnic said:
So I have my Sky Q HDMI out going to a manual HDMI switch, one leg goes to the TV in the front room (this works fine) the other goes via long HDMI cable to a TV in the bedroom. It's this TV in the bedroom I have a problem with. When the TV is first turned on there is picture but no sound. If I wait, after about 15 mins, the sound will come on and I'll have no problems with it until the TV is turned off.

If I disconnect the HDMI at the back of the TV and reconnect it there is instant sound.
If I plug the cable directly in to the Sky Q, taking out the switch, it works. Again instant sound when the TV is turned on.

A full power off of the TV (at the mains) doesn't help.
Changing audio formats on the Sky Q box doesn't help.
Picking 720 rather than 1080 (to reduce the bandwidth) doesn't help.

I guess this is a HDMI handshake issue but why do I have to wait 15 minutes when disconnecting the cable and reconnecting always results in the sound working.

TV is a Sharp 50FJ2K, it replaces an old LG LCD TV that worked fine until it went pop.

Any practical things I can do to fix this please?
Click to expand...

The 20ft cable works direct from the Q box to the Sharp TV, and also via the splitter, so the cable isn't really the issue.

Connecting a Q box or any source device to a HDMI ARC socket on a TV is no different (better or worse) than any other HDMI socket unless it's HDMI 2.1 for gaming at high frame rate, which doesn't apply to the Q box, so ARC or not isn't the issue.

Question: The bedroom set is 4K UHD. Is the lounge TV also 4K?

Question: Is the splitter powered from the Q box HDMI socket / TV USB port, or running from its own wallwart mains transformer?

Question: Is there a sound bar or some sound system connected to the ARC port on the lounge TV?

Question: Are there any little dip switches for EDID settings on the splitter?

I would agree that this sounds like a HDMI handshake issue. You've done the troubleshooting to eliminate other potential problems. If I were on-site, my next course of action would be to try a splitter with EDID control so that the Q box sees both TVs as the same spec for picture and for sound.

A TV on its own will generally appear as a stereo audio device. One with a basic sound bar connected should present as the same. Where a sound bar can process DD then the sound will look different between the two TVs, so that will set up a bit of a conflict. In addition, the source signal from the Q box will alternate between DD and PCM depending on the channel being played and the advert breaks.

I can't guarantee that an EDID-spoofing splitter will nail the issue, but I'd be surprised if it doesn't.
 
lucid said:
Question: The bedroom set is 4K UHD. Is the lounge TV also 4K?
Click to expand...
Both are 4K. I don't pay for Sky's UHD so the Sky Q's picture output is set to 1080p

lucid said:
Question: Is the splitter powered from the Q box HDMI socket / TV USB port, or running from its own wallwart mains transformer?
Click to expand...
It's actually a switch I have, only one output active at time. There is no PSU.

lucid said:
Question: Is there a sound bar or some sound system connected to the ARC port on the lounge TV?
Click to expand...
Neither TV has a sound bar connected. I did have the TV connecter to a Denon Amp but I've stopped using that. I'll double check I have done as I claim.

lucid said:
I would agree that this sounds like a HDMI handshake issue. You've done the troubleshooting to eliminate other potential problems. If I were on-site, my next course of action would be to try a splitter with EDID control so that the Q box sees both TVs as the same spec for picture and for sound.
Click to expand...
I guess these are expensive? Could you recommend one?

lucid said:
A TV on its own will generally appear as a stereo audio device. One with a basic sound bar connected should present as the same. Where a sound bar can process DD then the sound will look different between the two TVs, so that will set up a bit of a conflict. In addition, the source signal from the Q box will alternate between DD and PCM depending on the channel being played and the advert breaks.
Click to expand...
The lounge TV is a LG OLED (OLED55E6V), the last they did with 3D. They claimed the in-built sound system was like a sound bar, could it be presenting that via the EDID to cause this confusion?
 
picnic said:
It's actually a switch I have, only one output active at time. There is no PSU.
Click to expand...

picnic said:
I guess these are expensive? Could you recommend one?
Click to expand...

picnic said:
The lounge TV is a LG OLED (OLED55E6V), the last they did with 3D. They claimed the in-built sound system was like a sound bar, could it be presenting that via the EDID to cause this confusion?
Click to expand...

Thanks for the new information.

Regarding EDID management, a simple pass-thru device is quite cheap. They start at under £20 (see eBay item #134702630760). Something like this would sit before a splitter/switch and set both the image resolution and audio format. In this case, 1080P 50Hz 3D 2ch, or just 1080p 50Hz 2ch.

I have to be honest and say that the idea of adding two more HDMI junctions when one of the output cables is 20m does worry me a little. Setting the Q box to 1080i (its true native output) would take some of the pressure off the HDMI signal chain. 1080p at 25Hz requires about 10Gbps, whereas 1080i 50Hz needs just half the bandwidth. As a side benefit, the TV are generally better at converting 1080i source signals to 1080p or 2160p than a Sky box, so there's a potential for (marginally) better picture quality.

There's something else that I think might be contributing to your difficulties. It's the switch. I see these on sale at Amazon and eBay. The ads suggest that the products are bi-directional; a switch can be a splitter, and a splitter can be a switch. All this without the need for an external power supply too. HDMI includes a 5V power rail, but its purpose isn't for powering peripheral devices. The function of it is to power the HDMI chip in whichever device (source or sink) that doesn't have a mains supply at the time they're connected. This is part of the HDMI handshake process.

Unpowered peripherals might work okay when the cables are short, and it might be possible to get away with bidirectionality too. I just wonder though if the combination is the reason you're having some difficulties.

If you need it, I have a CYP 1-in:2-out HDMI splitter. The model is QU-12S1A. It's the one that has audio break-out too, not that that is much use to you.
 
Thanks again @lucid that's all great info. I've managed to find the details for the switch and you're insight is spot on. It is a bidirectional device.

I see the CYP is also an amplifier which I assume should help with the long cable run to the bedroom.
 
picnic said:
Thanks again @lucid that's all great info. I've managed to find the details for the switch and you're insight is spot on. It is a bidirectional device.

I see the CYP is also an amplifier which I assume should help with the long cable run to the bedroom.
Click to expand...
All splitters should be amplified. Passive splitting reduces the signal by slightly more than half. Amplified splitting should result in 100% signal for both outputs.
 
Buy a cheap HDMI switch which is powered and the problem may go away. Even at 1080p though, expecting HDMI to work at 15-20m length even without going through a switch, is in my experience flaky. I run a HDMI over ethernet setup to send 4K out of our Virgin box to a TV. The distance is probably also around 15-20m.

Sirrel Squirrel said:
Probably doing more damage completely turning it off every time you switch HDMIs especially if it's an OLED
Click to expand...

How so?
 
Following mainly the help from @lucid I've acquired a HDMI 1 in 2 out splitter. This seems to be working pretty well even with my 'unrealistically' long HDMI cable to the bedroom.

Thanks all.
 
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