Hi all,

I just built a new house and ran some 1" ID tubing primarily due to the ever changing video interface world, damaged cables, etc. Today, my friend and I painstakingly ran the following:

Two 10m of the Parts Express HDMI 1.3 Flat cables: http://www.parts-express.com/pe/pshowdetl.cfm?Partnumber=181-796&FTR=HF13C210&CFID=3573001&CFTOKEN=49812310

Two Monoprice HDMI plates: http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10425&cs_id=1042501&p_id=2813&seq=1&format=2

...which we then connected a Toshiba HD-A3 HD-DVD player to my Philips 42" LCD across the room with two random high-quality (aesthetically anyway) Monoprice HDMI 1.3 cables w/ ferrite beads.

The result was disappointing. Each port had the same problem: brief flashes of the HD-DVD logo, but mostly a saturated green grid, green lines, or a full green image.

I then thought that maybe the run was too long for these flat cables, so I removed one of the wall plates from the equation and the problem was downgraded to just a very light amount of white snow over the expected HD-DVD image.

If I leave the wall plates in, but take the 10m cable out of the equation, the problem goes away completely. So while the wall plates are probably causing some measurable amount of impedance, it's not the sole culprit.

I cannot test without at least one wall plate due to the length of the cable. I need to extend it another 4 or 5 feet to reach the TV. And no, I did not test the cables before I ran them- in hindsight I should have, but the TV and it's equipment were still boxed up.

My question is this: What's the most inexpensive way to solve this problem without sacrificing any measurable amount of latency? I play a lot of games on my setup, so latency is definitely a party-killer.

Would more ferrite beads do the trick? Better wall plates? Or did we tug on the cables too hard (although we have two cables doing the same thing here)?

I know that some flat HDMI cables have pretty bad performance characteristics; I don't know whose cable Parts Express is selling, so can't say anything specific to their product, but I would at least consider the possibility that you simply need to swap out that cable for something with better impedance control. That is more likely than anything else to fix your problem.

Ferrites are irrelevant, unless you have some reason to believe that you have a fantastic amount of RFI, and even then, it's unlikely that noise has anything to do with your problem. Wallplate quality doesn't vary all that much; all of them will produce impedance bumps.

Latency will not be an issue no matter what you do here. The difference between cables in signal velocity is in the range of a few microseconds for a 30-foot run. Total delay is probably under 40 microseconds or so.

Kurt
Blue Jeans Cable (http://www.bluejeanscable.com/store/hdmi-cables/index.htm)

Thanks for the help, Kurt.

Do you think that something like this (http://www.monoprice.com/products/product.asp?c_id=104&cp_id=10419&cs_id=1041907&p_id=2849&seq=1&format=2) could solve my issue?

Thanks again.

Sounds like, as Kurt says, you need a better cable.

The product you list is a repeater, which might help if you put that in the middle of your cable, but obviously that's not going to be possible, so no it's not likely to help you out much at all.

Now, as to your original post, I am confused as to what you tested. You originally describe parts express flat cables, but then you also describe two Monoprice HDMI cables. Which failed, what was the length in question? I am confused as to what the actual setup is.

okay, re-reading it sounds like you have two short monoprice cables connected to wallplates which are connected together by the long 10m flat parts express cable?

I am skeptical of flat data cables in general, which are not at all ideal performers, and 10m is pretty far, especially with wallplates in the mix. I would suggest pulling another HDMI cable through the conduit, better than that flat one. Many options, and quite frankly what Kurt sells is exceptional.

I also have to commend you for pulling conduit, which is the ONLY foolproof HDMI solution. Imagine the situation you'd be in now if you had this cable stuck in the wall, failing you, with no way to replace it. Good forward thinking!

Quick note: the Monoprice device you link to would actually go at the very end of your link right before your display. It is an equalizer and not a repeater, even though the website lists it as an "Active Equalizer Extender Repeater". It is possible it could help out, but like Chris and Kurt I have reservations about the performance of flat HDMI cables.

BTY the equalizer has only a couple hundred picoseconds of latency so that is a non-issue.

As you noticed, running HDMI through wall plates can cause problems due to the reflections they cause at high frequency. Although it's not as pretty, I recommend running a contiguous cable from source to display using gang plates to pass the cables through.

Here's my setup for more clarification:

Source -> 3' Monoprice cable -> Wall Plate -> 10m Parts Express Flat cable -> Wall Plate -> 3' Monoprice cable -> TV

I appreciate the advice guys. I was just able to do another experiment:
I remembered I had an unused 25' PE round cable that I had not used. It's shorter by about 8', but I figured it couldn't hurt to try it. I put it in the same configuration above, substituting the 10m/33' cable for the 25' cable.

RESULT: Light snow, with intermittent video/audio dropouts. I then removed 1 wall plate and all seemed to be fine. But the wall plates definitely seem to exacerbate the poor performance of the flat cables.

Considering the results of that experiment, plus the cost of the flat cables and the amount of blisters on my hands from running the pair through 1" ID conduit, I think I'm going to try the equalizer, hiding it right behind the last wall plate. I might even try chaining two of them.

I also think that the source, my Toshiba HD-DVD A3 player, could be a culprit. I've never been impressed with it. Also, my Philips 42" 720p TV is kind of "old" (2005 model), and the RX HDMI chip in it is most likely pretty poor. These two devices have fought in the past- I always just chalked it up to HDCP (which I absolutely loathe), and I'd grumble and turn them both off and try again. The symptom in these cases was typically a very distorted/green image. The image would get crunched to one side, and flicker like mad, again with a lot of green. And this was with a single 6' HDMI cable; no wall plates. I have a feeling that if I replaced my TV/source could be the primary culprits, but I'll have to make due with what I have (after all just built a new house ;)).

Thanks again guys. I'll post my results.

The Parts Express flat cable is category 2 so I would think it should work.

As FOD noted, the Monoprice device is actually an equalizer which compensates for the distortion due to the high frequency rolloff of long cables. Using two of them won't work any better than one for this purpose. It uses this device http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4444 to do the equalization, which states it can allow HDMI transmission up to 36 meters.

The Parts Express flat cable is category 2 so I would think it should work.

Are you sure about that? The reason I doubt it is that I have never seen a Category 2 certificate for ANY cable longer than 25 feet, which is the length we are certified for on the Series-1 bonded pair.

I have been seeing a lot of people misrepresent the Category rating of cables online. What they'll do--innocently, perhaps, because web catalogs aren't necessarily written up by the people with the best product knowledge--is take a cable which is certified Category 2 at some distance, say, 10 feet, and then assume that this certification applies to the cable at all lengths.

If somebody says he has a 10m Category 2 cable, my answer would be to ask him to show me the compliance testing certificate. Maybe PE's cable supplier has one at 10m, but I doubt it.

Kurt
Blue Jeans Cable (http://www.bluejeanscable.com/store/hdmi-cables/index.htm)

What Kurt said.
Kurts Beldon HDMI (7 meters I think) is the longest that I know of.

The Parts Express flat cable is category 2 so I would think it should work.

As FOD noted, the Monoprice device is actually an equalizer which compensates for the distortion due to the high frequency rolloff of long cables. Using two of them won't work any better than one for this purpose. It uses this device http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4444 to do the equalization, which states it can allow HDMI transmission up to 36 meters.

In addition to what Kurt already said, I would be very suspicious of this claim because they are making this claim on a flat cable...

Are you sure about that? The reason I doubt it is that I have never seen a Category 2 certificate for ANY cable longer than 25 feet, which is the length we are certified for on the Series-1 bonded pair.
Kurt
Blue Jeans Cable (http://www.bluejeanscable.com/store/hdmi-cables/index.htm)Well, I'm not even sure the sun will rise tomorrow. I'm just going by what the Parts Express website stated which was that it was HDMI v1.3b category 2 ATC certified.

So why is flat cable worse than round cable for performance? It would seem that a flat cable would be quite uniform which would contribute to good impedance characteristics. What am I missing?

So why is flat cable worse than round cable for performance? It would seem that a flat cable would be quite uniform which would contribute to good impedance characteristics. What am I missing?

I'm not sure flat cable is always bad; in fact, there's been some talk between me and some of the Belden engineering people about doing some flat-cable experiments, not something we'd be interested in if we thought it'd just be lousy.

Bear in mind that this isn't "flat" like ribbon cable, though. We're talking here more like something which has conventional twisted pairs, but then instead of being twist-cabled together, has the pairs laid alongside and a jacket extruded over. I don't know what the particular ups and downs of that sort of process are, but can imagine various ways that the cable could be adversely affected--for example, by periodically-varying pressure on the pairs as they twist with relation to the jacket. Without knowing more about how the particular cable is made, however, it's hard to guess what might be causing the issues.

Kurt
Blue Jeans Cable (http://www.bluejeanscable.com/store/hdmi-cables/index.htm)

Kurt,

I spent almost a full hour on your website today- the information you've compiled is fantastic. I am an electrical engineer (digital ASIC designer though, so I still consider myself a newbie for macro-level transmission lines), and I found the information very impressive. Between that knowledge base and your help on these forums, for what it's worth, "next time" I have a project like this I will be going to your site first for my cables.

RESULTS:

The $25 monoprice "HDMI Extenders/Equalizers" worked! All I used is one right before the last wall plate. Amazingly, it seems to have solved 100% of the video/audio issues I had over the 35-40' run. This is even with the wall plates in the system. Very pleased.

Thanks to everyone for their advice. It has been greatly appreciated.

RESULTS:

The $25 monoprice "HDMI Extenders/Equalizers" worked! All I used is one right before the source. Amazingly, it seems to have solved 100% of the video/audio issues I had over the 35-40' run. This is even with the wall plates in the system. Very pleased. Interesting that it works at the source. It's designed to be used at the TV end of the cable to equalize the cable losses.

I'll bet Tempest actually meant right before the display. Glad to know a part I have been heavily involved with helped with the situation.

Interesting that it works at the source. It's designed to be used at the TV end of the cable to equalize the cable losses.

I'm sorry- I misspoke. I must have been tired when I wrote that. I should have been more specific- I meant right before the *wall* source, so in other words, it's at the end of the chain, closer to the sink, right before the 2nd wall plate:

SOURCE -> HDMI Cable -> HDMI Wall plate -> 10m HDMI Cable -> Monoprice Equalizer -> HDMI Cable -> HDMI Wall plate -> HDMI Cable -> SINK (TV)

That way if I ever sell the house the next user doesn't have to worry (or even know) about the extenders, since they're hidden in the wall.

Thanks again guys!