[Adam81OSU]

Just got my first dedicated home theater room setup finished yesterday. Watched tv and played xbox 360 all night with my wife and had a PERMA-GRIN on my face - What an experience! Only problem though? Signal issues!


I have a Mitsubishi HC3800 and am running a 35 foot HDMI from a Rocketfish 4-Port HDMI Switcher (that IS 1080P compatible) which then routes out to my Sony BDP-BX2 Blu-Ray, my Xbox 360 w/ HDMI, and my Cable box (HDMI).


I have zero issues playing Xbox or watching digital cable. When I try and watch a DVD (regardless of if it's DVD or Blu-Ray DVD) the first 10-15 minutes I get flickering and all-out signal loss for sometimes as long as 5-7 seconds VERY frequently. Once it seems to get going though, signal loss is less frequent then alltogether non-existant.


I've read elsewhere that some Blu-Ray players put out a weak HDMI signal, is that 35 foot HDMI killing it? I'd like to think it's NOT the Rocketfish as my Xbox 360 is having no issues and it's 1080P as well.


Other than getting another Blu-Ray over here to test this, what do you reccommend?


If I go with an HDMI repeater/booster, would it be smarter to return the 35 footer (please say no!) and replace it with two smaller HDMI's and put the repeater midway inbetween? Or would it be okay to run the repeater/booster RIGHT off the back of the Rocketfish then run the 35 footer to my projector.


Any advice would be awesome - It's great to have mysetup complete but if I can't see its full potential by watching a Blu-Ray I'm bummed!


Oh and yes the obvious solution would be to replace my receiver to a newer model with HDMI's on it, but I'm trying to go a financially sensible route this time as I've already dumped thousands in the last 30 days and am trying to satisfy my wife's need to slow down

 

[reconlabtech]

You either need a better HDMI cable or a better switcher or both. Run the 35 footer directly from the BD player to the PJ and see what happens.


Visit monoprice.com or bluejeanscable.com to get high quality cables without breaking the bank. Switchers too.

 

[BobL]

Get a signal restorer and put it near the projector. I recommend ones by Ethereal or Spectrum Electronic Solutions. A different cable might not solve your problem.

 

[mnnc]

Try the direct route first as suggested and go from there. If it persists it could be cable or pj. I read somewhere in the mits 3800 thread about like problem/s. Does the pj have an option for hdmi signal? Also chk the dvd players settings...could be dvd player. Basically you will have to solve by process of elimination so take caution...don't rush out and upgrade hdmi cable as it may or may not be issue.

 

[reconlabtech]



Quote:
Originally Posted by BobL /forum/post/18174224


Get a signal restorer and put it near the projector. I recommend ones by Ethereal or Spectrum Electronic Solutions. A different cable might not solve your problem.

You cannot restore lost data. You can amplify what signal is left but it will always be lower pq than the original image. You MUST use a better cable.

 

[BobL]

The data is not necessarily lost but part of the signal fell out of HDMI spec and the equipment isn't accepting it. Which isn't surpising since it was only designed for a total distance of 16.5 feet. This distance is the total distance from source to display not just the length from the receiver to the display.


We get away with longer cable runs because 1080P uses slightly less than 1/2 of the bandwidth of the HDMI 1.3 spec (HDMI 1.4 didn't increase bandwidth only capabilities). If you run 480P you'll have even better luck with long runs. The OP is OK at 720P (?Xbox) or 1080i but not 1080P, it sounds like a bandwidth problem due to long cable runs. Plus with digital signaling there is no difference in picture quality when it works. If you have bad signal integrity it won't work.


You can correct voltage, timing, capictance, etc. with the devices mentioned. Plus these devices are made for runs up to 150ft with a good cable at full bandwidth. If it doesn't correct your problem it can help to determine where the problem is either the equipment or cable.


The advantage of using a device like this is future proofing your system. If you think you see a lot of HDMI problems now on the forums wait until we start getting sources that use greater bandwidth like 3D, 4k x 2K, etc.


I don't have any relationship with the companies that make these devices. I've dealt with these type of sginaling issues whe I worked on mainframes many years ago and being an installer and dealing with HDMI problems since it started I can tell you what works. You can try the cheaper devices as well as cheaply made cables (cost doesn't necessarily equate quality) believe me we have. We now use cables with a DPL rating of 3 or better and use the signal restorers for lengths greater than HDMI spec but under100 feet. We use fibre for longer lengths.


You can do a simple test and set up your system with all short cables (

 

[Michael Sargent]

As Recon said, look at Blue Jeans Cables. I run one of their 45' certified cables to my AE-4000 and have never had any problems what so ever. And the price was great!


Mike

 

[cjsiv]

There are some bad reviews for that switch on the best buy website if it's the rocketfish switch they sell. All our input is irrelevant until he bypasses that thing and plugs in direct. I use a monoprice 4x2 switch with a 50ft cable from amazon for $22 and it works flawless to my epson with both 720p and 1080p. I'm betting on the switch.

 

[BobL]

It could be the switch but bypassing it doesn't prove it is the switch. Try it with short cables and if you still have problem then look at replacing equipment. Otherwise it is a signaling issue plain and simple. A different cable might work or it might not. Because some get lucky with longer cables others won't. You won't have to search long to find problems on any forum with HDMI and longer runs.


But everybody wants to blame the equipment when we are using the interface with lengths for which it wasn't designed. I'm not saying all equipment is good but it has gotten better over the years. If you are using the interface in a capacity that is greater than what it was designed then remove that variable first when trying to diagnose the problem.


Look at some cable tests from audioholics and you'll notice some start to fail at the >30' foot mark for 1080P 8 bit (less than 1/2 HDMI bandwidth) but almost all longer lengths work at 1080i except a few at ~50'.

http://www.audioholics.com/education...esting-results


Now this test is just testing single cables. If you add a switch (or receiver) and another several feet of cable to the source your chances for not getting a picture just increased.


This is why it is important to test with short cables. It is possible to get a short cable that causes the problem but much less likely. If possible test with short cables that are certified by Simplay HD or DPL with a rating better than 3.


I can't stress this enough. You can really chase your tail trying to swap out equipment and cables.


Hope this helps.


Bob

 

[cjsiv]



Quote:
Originally Posted by BobL /forum/post/18178895


It could be the switch but bypassing it doesn't prove it is the switch.

If you run the 35 ft cable from the bluray player to the projector and it solves the issue, it proves the switch is bad and the cable is fine.


If you had that setup and the switch was the known weak link due to bad reviews and faulty reliability, wouldn't you start there before you bought new cables or a signal amplifier?


I was having screen "tearing" issues with bluray. DVD, tv, and video games were fine. I am well aware of the problems with long runs of hdmi cable. I also was not a fan of using switches, but now I am feeding a projector and a plasma so it was a must. My first thought was it was the 50ft cable. I hooked it straight into the ps3. That was quick and easy since I didn't have to pull my components out of the rack. Still there. That ruled out the switch real quick. Pulled out the ps3 and hooked it up with a 6ft cable. Still there. Turns out it was the 24fps setting in the display menu which my projector doesn't support. The OP also needs to check the output settings of the bluray player to see exactly what kind of signal he is sending to the mits. It may not like one of the advanced settings. (RGB, full, limited, 24fps, etc.)


My current setup is a Dish 722, PS3, Xbox360, and dvd player all into my Denon 1910. The Denon switches and scales the inputs and sends to a monoprice 4x2 switch via a 6ft hdmi. Then 25ft and 50ft hdmi cables run to the displays. Video signals look great on both displays. All my cables are from amazon.


Maybe it's the bag of chicken bones I shook over everything before I turned it on

, but all is working well.

 

[BobL]

cjsiv,


I've worked with LVDS and TMDS and it doesn't work the way you think. I understand your logic and can see why you think the switch might be the problem. Part of this is most people think these switches (and receivers, etc.) regenerate the signal and send out a perfectly clean signal to the display. If this was the case it would be easy to diagnose these problems and your logic of it works direct would be true.


Unfortuntely it is not and with HDMI the source likes to talk to the display for EDID and HDCP verification. The switch or other device identifies itself to the source and the display. It is then as part of the chain and the system needs to be thought of as a whole.


Switching components or cables without testing the system is not the correct way to approach for diagnosing a problem. If something works direct does not mean it will work when you add another cable and device in the middle.


Since HDMI wasn't designed for long lengths it is the first variable that should be removed in testing. If the system doesn't work with short cables then try to figure out which device is causing the problem. Just switching devices because one is guessing which device is the problem is just wasting time in my opinion. You may get lucky or you may not.


If the OP was to purchase a new switch I'd recommend the ones by Spectrum or Parasound. They are the only ones I know that have some of the SR-1 restorer circuitry built in. But, they are no where near as inexpensive as other switches. But they work and solve other problems!


Bob

 

[crosen]



Quote:
Originally Posted by BobL /forum/post/18175100


The data is not necessarily lost but part of the signal fell out of HDMI spec and the equipment isn't accepting it. Which isn't surpising since it was only designed for a total distance of 16.5 feet.

I'm wondering where the idea that HDMI is designed for a total distance of 16.5 feet is sourced from. I have not encounted this in any of the HDMI design/spec literature.

 

[threed123]

Okay, lots of similar issue in the HC3800 forum. I have a monoprice switcher with PC, Blu-ray and cable box going into it with 3 to 6 ft cables. Out is a monoprice.com 24awg 20 foot cable to projector. It took me no less than six different cable from the blu-ray to the switch until I found one that worked, then I had to set the HC3800 to "see" the whole cable (from blu-ray to switcher to projector) as just two meters long. No other length setting would work. The strange things is that the blu-ray worked with a 6ft. two-year old hdmi cable, while the PC and cable box required newer 3 ft cables. My point is with that kind of setup you've just got to try, try, try different cables and options.

 

[BobL]

It is not part of the spec but mentioned in the design criteria of DVI which HDMI was built upon. 5 meters (~16.5 ft) is what it was designed for and never intended for long runs. At 1080P you can definitely do longer runs but higher resolutions and 3D will increase the bandwidth requirements. Blue jeans cable 25 foot cable passed HDMI category 2 which will cover the increased bandwidth.


When HDMI certifies a cable it is just for that length not for multi cable applications with repeating devices (switchers, receivers, etc). DPL gives a nice rating system and includes ratings for cables likely to work in multi cable applications. DPL said the longest they have had pass is 6 meters but their requirements are a little more strict and it gives a rating from 1-5. Anything with a 3 rating or higher is for use with repeaters.


Bob

 

[reconlabtech]



Quote:
Originally Posted by crosen /forum/post/18323433


I'm wondering where the idea that HDMI is designed for a total distance of 16.5 feet is sourced from. I have not encounted this in any of the HDMI design/spec literature.

It's not - in fact it was assumed in committee no cable would be longer than 6 feet since everyone puts their tv and player/signal source together so a distance factor was never considered.

 

[crosen]



Quote:
Originally Posted by reconlabtech /forum/post/18324115


It's not - in fact it was assumed in committee no cable would be longer than 6 feet since everyone puts their tv and player/signal source together so a distance factor was never considered.

That's consistent what the info I've come across.


Do you know where I can find info on the behavior of an "HDMI repeater?" I'm referring to the repeater function that an AVR performs when sitting between an HDMI source and display. I'm looking for details on how a repeater behaves in connection with proper setup and troubleshooting of HDMI issues (part of my ongoing effort to strengthen my hand when fighting with HDMI components.)


BTW, I found the HDMI cable info at Blue Jeans Cable to be really terrific.

 

[Blue Rain]



Quote:
Originally Posted by cjsiv /forum/post/18177444


There are some bad reviews for that switch on the best buy website if it's the rocketfish switch they sell. All our input is irrelevant until he bypasses that thing and plugs in direct. I use a monoprice 4x2 switch with a 50ft cable from amazon for $22 and it works flawless to my epson with both 720p and 1080p. I'm betting on the switch.

Hi


I will be needing 4x2 switch soon myself. Can you post the link of the switch you bought ..thanks

 

[BobL]

HDMI, DVI, 8b/10b (TMDS/LVDS) which everything is built upon comes from the computer world where components are rarely far distances apart and even more rare in the computer world is to have a device in the middle.


Historically DVI in computers never caused as many problems that HDMI does in consumer electronics. And further back 8b/10 never had as many problems either and that was high speed signaling in its infancy. HDMI was built upon existing reliable technology and applied it to the consumer world where it is being used in ways it wasn't designed.


HDMI works when everything is manufactured and used as designed. However, there has been some poorly manufactured equipment and cables to further complicate issues. The other complication is the standard has been a moving target, 10 versions in 8 years keeps manufacturers trying to add the latest and greatest features while maintaining compatability with previous versions. I hope 1.4a stays around for a while.


Bob

 

[BobL]

Crosen,


Here is part of the Blue Jeans Cable "What's the matter with HDMI". BTW, I just read it and it is good basic info and I agree that HDMI is not a good standard for consumer applications but we re stuck with it. For people that want the whole link.
http://www.bluejeanscable.com/articl...-with-hdmi.htm


"Third, eliminating unnecessary switches, couplers, and adapters may help; as bad as the impedance mismatch problems are in the cable itself, those problems are even worse when the cable's conductors must be split out to join to a connector, or when the signal must travel through connections that can't be kept at 100 ohms."


This just shows we have to consider the whole system and not just cables between point A and B.


Capacitace and impedance interact with each other, raise the capacitance and it will lower the impedance and vice versa. Instead of thinking of this as one long cable as I tried to explain in the past. Think of the repeater chips function as not only to re-transmit data but to balance the lines of the input and output. There is only about a 15% tolerance in this matching and the chip might not have enough to correct for both input and output especially when one is a longer run.


From a PCB board layout design paper.


"It is imperative that the switch (refers to HDMI switching chip, like in receivers AKA repeater) be optimized to match this characteristic impedance. Any imperfections of the board layout will cause reflections which degrades signal transmission to the HD monitor. Think of reflections as signals that are lost between the inputs to the output. Utilizing careful RF and Microwave layout techniques minimizes these reflections."


Now this quote is talking about board layout but the cables are merely an extension of the board. The traces goes to a connector which the cable plugs into. The term "reflections" is also called echos or back feeding. And these can be measured with a time domain reflectometer.


As we get deeper into this is what happens to the signal. There are a number of problems that can happen. Voltage drop is one of them, change of the waveform is another. First is we have to remember 1s and 0s are electrical signals and not numbers being transmitted. We start with a square wave (I won't get into discussing the fourier transform and harmonics at the moment) and as we have capacitance/impedance problems that square wave now looks like a sine wave or what I call a "shark fin" wave. Why is this bad?


You would think if the wave is tall enough (ie has enough voltage) it would still be received just fine. But the wave has to be wide enough so as it passed through the receiving unit it has time to recognize it. Now when a square wave rounds of it corners it becomes more narrow making it tougher to recognize.


Keep in mind this data is moving very fast, near the speed of light. Timing and recognition of data are critical. We are measuring time in billionths of a second (nanoseconds) and the rise times of the wave in trillionths of a second (picoseceonds).


HDMI is a complex interface and a repeater circuit is probably one of the most complicated in the HMDI chain. There are SI (signal integrity) engineers that design and handle these type of problems at the manufacturing level for circuit board design.


Hope this helps.


Bob

 

[crosen]

Bob,


If I'm not mistaken, the design paper quoted is describing an HDMI switch in which there is HDCP transparency. I imagine in this scenario, the upstream and downstream links are bitwise identical. I further imagine this allows for simple circuitry with tight coupling between switch input and output.


However, this is not the case with a typical AVR where the upstream HDMI link (from the source) is decrypted and then rencrypted for the downstream link (to the display.)


I am interested in learning about the scenario for a typical AVR.


Thanks,


Cliff