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Long HDMI cable

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  • Long HDMI cable

    If I want to run a long HDMI cable from a BluRay player from the auditorium to the projection booth, am I going to see a lot of picture/sound degradation? I'm thinking somewhere between 50 and 100 feet.

  • #2
    You cant run HDMI that long - what you can do (and what we did in your same situation) was buy a HDMI over ethernet extender. It lets you substitute a long ethernet cable for the hdmi. It works very well.
    Here is a link -
    Its not the same as what we used but looks about the same.

    Good luck !


    • #3
      You may use active cable converters, as the type mentioned by Armand, or try one of the active HDMI cables with integrated optical transmission ('optic' or 'fibre' HDMI cables). 50-100 feet should work nicely with both means. Avoid those CAT5/6 converters that need two network cables to function.


      • #4
        Originally posted by Carsten Kurz View Post
        You may use active cable converters, as the type mentioned by Armand, or try one of the active HDMI cables with integrated optical transmission ('optic' or 'fibre' HDMI cables). 50-100 feet should work nicely with both means. Avoid those CAT5/6 converters that need two network cables to function.
        I second that .... the first extendor we tried used 2 cat 5 cables , was bad. Use one that runs on a single cat6. We've had excellent results.


        • #5
          we have had good luck with blackbird


          • #6
            The maximum length of an HDMI cable is 3 metres or 15 metres, depending on whether you're sending 4K resolution or 2K.
            (3 m. for 4K, 15 m. for 2K.)

            If your cable run is less than 50 ft. and you're not sending 4K, you might be able to squeak through with a long cable, assuming you buy good quality cable, terminate the connections properly and ensure the cable is run in a way that avoids interference.

            I have done things like that when I worked at Mercyhurst. We ran cables through conduits, from the control booth to remotely mounted projectors and other equipment on several occasions.

            Just be sure you use good quality cable with proper shielding, make proper solder joints and all that good stuff.

            At one venue, we decided that the cost of buying cable, installing conduit and doing all the other work wouldn't be worth it, even though it would have been just under the maximum distance. Instead we bought a converter box similar to what Armand describes.

            It worked perfectly and, IIRC, ended up being cheaper than running the HDMI.


            • #7
              15m on 2K? Straight up? Good luck with that! It is 15-feet, even on 1080p/60 stuff. You need to check the cable specifications. A 1080p/60 system should be able to handle 10.2Gbps data throughput. A UHD (4K) system should be able to handle 18Gbps throughput. Note, on 4K, you can have 4K, you can have 12-bit color and you can have 4:4:4 color depth and you can have 60Hz...just not all at the same time...18Gbps is the top end of the spec and once you go past 30Hz, something has to give (normally that 4:4:4 turns into 4:2:0 to get to 60Hz.

              Screen Shot 2021-01-10 at 7.52.59 PM.png

              Similar tradeoffs happen for 1080p to get to 10.2Gbps. However one typically stops at 8-bit color and 4:2:0 for movies but it depends...if you are doing high detail color graphics for a power point, that 4:4:4 can be important. As you bandwidth goes up, so does your cable's thickness as it needs larger wires and more shielding/isolation to get the signal from one end to the other. The only way you will get 1080 content 15m (about 50-feet) is if you have very low bandwidth content. You might get away with it on movies running only at 24Hz and decent cable but it won't be small and it will likely fight the pathetic HDMI connector.

              Most HDBaseT products out there will likely accomplish what you want. Be sure to use shielded CAT5e or CAT6 (shielded CAT5e beats unshielded CAT6 for this application).

              One interesting thing that is happening in the A/V world and I'm sure will trickle into the home is HDMI over IT type stuff where HDMI signals can travel over a conventional IT infrastructure. Naturally, particularly at the moment, depending on the content, it can be rather piggish on the bandwidth it consumes. However, in a multiplex where you might want to have several theatres equipped for A/V you can do so with minimal infrastructure and the cost of the endpoints continues to fall. Furthermore, it is no longer just a 1:1 relationship between the transmitter and could have a power-point show in on room and have an overflow in another.

              Anyway...if you are just sticking with 1080p stuff, the furthest I've gone for Blu-rays is 35-feet with some pretty fat cable and 25-feet for higher refresh computer graphics...again on some pretty fat cable. Once you get things down to 15-feet, you can get back to more reasonably sized cables.


              • #8
                You can get very long HDMI cables that convert the signal to optical and send it through a fiber cable, then decode it at the other end - up to 300 feet. I used a 150ft one for a special event a few years ago for a presenter wanting to use his Mac on stage. It worked fine for static Powerpoint slides, but full screen video at 1080p60 glitched out and put digital noise on the screen. I had to reduce the resolution quite a bit to get a clean picture.

                And in any case, these cables are no cheaper than an HDMI over Ethernet cable transmitter/receiver, plus a long, shielded length of cat6. Like Gordon, we've installed several of the Monoprice ones, and they've worked very reliably.


                • #9
                  Note too on these "active" HDMI cables for the longer run...they are directional with a distinct (labeled) source and display end. They do require power but often get it from the HDMI connector itself so your device has to be cable of supplying the power. Others have a USB cable comes out of one end to provide power to it. I've only tested these out to about 50 feet and they have been reliable and not horribly expensive.


                  • #10
                    Several years ago, I installed a 100ft generic HDMI "active cable" I got on Amazon from front of stage back to the booth at one of the screening rooms I work at. It's only used for meetings when a presenter has some sort of power point or other computer presentation they want to put on screen, and it has worked fine for that purpose. Near one end of the cable there's a small "sausage" shaped section about 3in long and a few mm larger diameter than the cable. and it houses the amp (or maybe it's a repeater?). It gets its' power from the cable itself. As others have pointed out, these cables are "one way". I KNEW that, but halfway through installing it I realized I had somehow gotten it turned around & had to rip it out & start over again.

                    At another screening room, we went the "Cat 5" video route, because we had a lot of Cat-5 tie-lines available, and pulling any type of new cable at this place would have been extremely difficult.
                    I can't remember the name of the unit we bought, but it was a 'rack-mount' system that cost about $600, and it transmits not only HDMI with with full audio, but it can also pass VGA and two additional audio channels. It's powered from the 'receiver' end mounted in the booth rack. Again, the application at this venue is primarily used to send a presenters' computer graphics from from a lectern in front of the screen back to the projector in the booth, and works fine for that purpose.

                    Occasionally (probably 1% of the time) I've had obscure, but annoying, HDCAP issues on both of these systems. It seems very random, so can't pin it down to any particular type of computer or graphics card. Fortunately, I've figured out a trick to get get around that when it happens, so it's never been a 'show stopper'. It just takes me a few more minutes to set up.


                    • #11
                      100ft is not yet critical (=cheap to solve) for HDMI extensions from my experience, and I have seen so called 'active cables' for these lengths.

                      It get's more complicated from 150ft on. Notebooks default to 60fps frame rate, while e.g. a Bluray will output just 24fps. That is enough difference for a notebook connection to fail in a critical constellation, while a Bluray Player works.

                      In one case with a critical cable length I actually solved the problem by setting the notebook frame rate down to 24fps. The lag of the moving mouse pointer was visible for me, but no one else cared. If the money is there, get an HDBaseT solution, they have come down in price considerably now. Up to and around 150ft, an active CAT5/6 converter using a single shielded CAT6 cable can be bought for as little as 50-100US$. Some allow to have an infrared transmitter feed for a remote as well.

                      I'm amazed how many unshielded CAT6 cables are still sold, just because they cost a few pennies less.
                      Last edited by Carsten Kurz; 01-11-2021, 06:08 PM.


                      • #12
                        I've had poor luck with the active HDMI over optical fiber cables. My go to on new installations has been Crestron DM (Extron also makes a similar product) and I will install "transmitters" and "receivers" in the auditorium for presentation and confidence monitoring purposes. DM is a point to point system based off of HDbaseT the new video over IP systems like Crestron NVX look promising. I did one install in a large office meeting complex with NVX and it seems to work well, I have also demo'd and been impressed with Visionary Solutions stuff.


                        • #13
                          We have one of those HDMI over Cat6 converter things at my theater we used this summer for our live concerts. The concert promoters tech guys used fiber optic cable to run 300+ feet from the video and sound consoles in front of the stage back to the projection booth, then they converted that to HDMI into the projection rack. We split the HDMI signal and sent a combined audio / video feed from the Screen 1 booth to the Screen 2 booth via Cat6 and re-converted back to HDMI in the Screen 2 booth. Worked like a charm. Picture looked fantastic on both screens.

                          At our Keith Urban concert, they ran 800+ feet of fiber optic cable all the way around the edge of the parking lot so people wouldn't drive over the cable. No issues at all.
                          We are getting ready to install 350+ feet of fiber from the screen to the projection booth as a permanent installation for future concerts.
                          Last edited by Barry Floyd; 01-15-2021, 03:55 PM. Reason: Added in notes about fiber


                          • #14
                            Fiber is great...the cost of the endpoints are normally the killer (but it is getting better) and, normally, for 300-feet or less, copper solutions are the cheaper choice and they work well (at least good ones like Extron and Crestron...and others).


                            • #15
                              A reasonably robust switch with 10 gig SFP+ slots in it starts at around $500, so multiply that by at least two (plus $50 for Chinese no-name transceivers or significantly more for brand name ones), and yes, the cost is significant.