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omnibeard's picture
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HDMI signal strength vs cable length
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Ok, this is driving me nuts, hoping someone can help.

Trying to finish off cabling in my house renovation... Two runs of HDMI cable from sockets at top of wall next to projector mount, one is 10m the other is 15m.

On both cables, either end is connected to a HDMI module socket, into which further HDMI cables (as short as poss) connect to projector at one end, AV kit at other. Everything hidden behind walls.

The only things I have at hand to test are the PJ, an old Panasonic blu ray and a Mac mini.

Mac mini will output signal fine on both cable lengths, no matter how many extra connections are involved - ie. I can just connect the long cables directly to PJ and Mac bypassing the extra connections of the HDMI module sockets, or I can use the sockets and extra cable. All good. Happy me.

The Bluray however is being a bit more problematic. It's very temperamental and doing some weird things, fairly consistently. For example, connect it directly to the PJ via the 15m length and it's not happy, lost signal, U73 error etc. If I put a 4 port HDMI switch between PJ and cable then it's fine, but not if I put the switch between bluray and cable. Which strikes me as v odd. Seems fine on the 10m run but again a bit temperamental.

So, a couple of questions...

Is a 15m HDMI cable asking for trouble?

Or is it just that the HDMI signal from a bluray is very weak (or maybe just this one, it's a very budget BD35) - as the Mac mini is having no such trouble.

If that is the case, I will be adding HDMI equipped receiver in once house less like building site - will this output a stronger HDMI signal when fed from a bluray?

And/or do newer bluray players suffer from weak HDMI output?

Obviously I could just have cable ends sticking out of holes in wall, not such a problem at PJ end as will be using joinery to hide stuff a bit up there anyway, but at other end would like the neatness of the HDMI module sockets.

Hope this makes sense!

 

omnibeard's picture
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RE: HDMI signal strength vs cable length

Actually, even with the 10m cable the bluray player is being temperamental. As soon as I start adding any extra connections to the chain (ie. using the module sockets and track lengths of HDMI cable) things are starting to go wrong, so maybe even a 10m run is not the best idea?

When the bluray is connected directly to the PJ using only the 10m cable then everything works fine.

spiny norman's picture
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RE: HDMI signal strength vs cable length

Sounds like the signal from the BD player is a bit feeble and you are suffering signal drop-outs with the multiple connections and long cable lengths. Either that or the projector is a bit marginal on the sensitivity of its HDMI input, and needs a bit more signal than your proposed set-up can deliver.

Might be useful to insert an HDMI repeater/booster in the chain between player and projector: these don't cost a fortune and will allow much longer cable runs.

Since the 4 port switch at projector end seems to solve the problem, then perhaps installing a repeater at that end will sort it, or you could go all belt and braces and install one at each end. They're not that expensive, and will be cheaper than other solutions such as HDMI over Ethernet.

omnibeard's picture
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RE: HDMI signal strength vs cable length

Yup, pretty sure it must be this as currently feeding Mac mini hdmi out via 1m cable to wall socket, then over the 15m cable, then from wall socket at other end via 1m cable to PJ and all is fine.

Is this a known issue with bluray players, a weak HDMI output?

Do you know if feeding bluray player into AV receiver via HDMI will boost the signal?

I'm guessing it will, but need to know for sure before boarding the wall back up. Yawn.

Cheers!!!

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RE: HDMI signal strength vs cable length

Not a known issue with BD players, but it seems you may just have an unfortunate combination of player, sockets, cable and projector giving rise to this problem.

No guarantee that AV receiver will solve it, so if it were me I'd be installing a repeater at the projector end of the HDMI cables and chelcking this solves the problem before making good. At least that way you're sure it'll be OK, and not just hoping it will when everything is finished. For the cost of a repeater or two, which will be less than £50 all-in, that sounds like a sensible precaution to me.

omnibeard's picture
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RE: HDMI signal strength vs cable length

You are correct, thanks!

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RE: HDMI signal strength vs cable length

I had a similar problem with a long HDMI cable and Blu-ray player/AV amp. The repeater solution didn't work very well for me either. I ended up using an HDMI over Cat 6 system (from Keene) and I've had no problems since. I'd suggest looking into that as a better solution than multiple HDMIs with various connections in-between. 

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RE: HDMI signal strength vs cable length

VoodooDoctor wrote:
I had a similar problem with a long HDMI cable and Blu-ray player/AV amp. The repeater solution didn't work very well for me either. I ended up using an HDMI over Cat 6 system (from Keene) and I've had no problems since. I'd suggest looking into that as a better solution than multiple HDMIs with various connections in-between.

Absolutely agreed that the HDMI over Cat 6 solution would be a better one, but I get the impression that the OP is already committed to the various cables/connection boxes mentioned, so advised a solution enabling those to be kept.

omnibeard's picture
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RE: HDMI signal strength vs cable length

Not really committed one way or the other as I haven't boarded the wall up yet so can get to everything, have ordered a booster to see if that does the trick, if not will revisit and see what needs to be done.

I've actually given myself too much cable anyhows, so could possibly lose the 15m cable and use the 10m instead, and use a 5m to get to where the 10m cable was going to go. Might be a bit tight. Will check. Yawn.

Thanks anyhows...

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RE: HDMI signal strength vs cable length

The other consideration is that, if the performance is already borderline, it may not be very future proof for when more data needs to be passed.

omnibeard's picture
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RE: HDMI signal strength vs cable length

That doesn't bother me too much, I'm more than happy with my PJ, don't really suffer from upgradeitis, am happy with DVDs as much as bluray.

Anyway, can always take a sledge hammer to the wall if I really need to!

I will get it sorted to deal with current tech though... The CAT6 thing is a def possibility if the booster and/or using shorter cables doesn't work.

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RE: HDMI signal strength vs cable length

Quick update - the booster/repeater thingammy does the job on the 10m cable in as much as I can now add as many connections as needed (ie 90 degree bend plus socket module on one end and same at other) and it all works fine, which was not the case previously. With the 15m cable however it's no dice.

So have just ordered some HDMI over Cat6 stuff, hopefully that will then be job done.

So thanks for the heads up on that VoodooDoctor, or may I call you VD?

Er...

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RE: HDMI signal strength vs cable length

Glad to be of help (and not an irritation).

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RE: HDMI signal strength vs cable length

 

Sorry to come to the party late but had many issues doing a similar set up and after many attempts ended up with 2xpowered baluns over cat6 cable and everything worked fine...even had to resort to using power baluns at each end of the chain a single was to problematic.

My problem was mainly due to a low output from my av procesor even the dealer couldnt get it to work over 5m which is pretty poor for a reasonable expensive piece of av gear..nothing is straight forward were hdmi's are concerned Smile

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