A longer cable does not affect picture quality - well atleast not in the traditional sense

When most people think of differences in picture quality, more often than not they think of differences in clarity along the lines of a turning a camera lens, with an image appearing either sharply or not so sharp, a little out of focus perhaps as a way of describing picture quality. And when people think of colour reproduction they think of blacks appearing more grey and washed out skin tones.

With regards to the images produced by a HDMI cable, the notion that an image will appear clearer, or colours more vibrantly with a short cable length and not as clear or vibrant with a longer length is totally untrue and actually technically impossible. In reality, a picture shown via a HDMI cable will either appear absolutely 100% perfectly, completely not appear, or appear with completely in-your-face, unlivable with visible errors, picture artifacts, normally green or red blocking, picture juddering or speckles.

This is an utterly different type of degradation in picture quality that consumers are used to from the analogue days of scart and composite connection, perhaps producing fuzziness and ghosting that people may have decided to live with. A common myth about HDMI is that picture quality or should we say ‘clarity’ can deteriorate over long cable runs. This is not the case.

HDMI is digital

At a very simplistic explanation level, the nature of a HDMI signal is that it is digital, a series of 0’s and 1’s, binary code, ‘on’ and ‘off’ signals. Essentially, the cable with either work or it will not. Digital is a lossless signal. If people say there is a visible difference in picture clarity, then their mind is playing tricks on them. The image will be absolutely identical to that of an image being produced by even a short HDMI cable length of say, 0.5 metre.

Of course, this explanation is very simplistic and there are other important factors that affect HDMI signals. For the super-technical this explanation does not adequately suffice, so if you are one of those techy people and wish to read a far more in-depth, highly technical assessment on the nature of HDMI, please read our article titled: 0’s & 1’s - Digital is Digital, Right?

So no problems with my long cable length and its picture quality - so what are the problems?

It is true to say that HDMI was primarily only designed to be used over short runs and can prove to be pretty sensitive for long distances. A lot of variables have an effect on the success or failure of the signal reaching the display.

One variable is the output signal strength of the device that the cable is being connected to. Different manufacturers and even different models from the same manufacturer can vary in their output signal strength. It has often been the case when conducting our own testing on this issue that the same 15 metre cable will work faultlessly with one manufacturer’s Blu-ray player but will fail on another. What is at fault here? Is it the cable or the device? The answer is neither, the solution is simply to use an alternative connectivity product. One that is better suited to the needs of that particular set-up. This is a frustrating and often annoying element of the nature of HDMI technology but we do have the products available to find the solution to most of these issues.

However, there is light at the end of the tunnel and it's important to note that most projector and display manufacturers are now adding cable EQ (equalization) circuits into their systems. This is a way to counteract the filter effects of a longer cable and help the system to correctly read the digital data. In addition, HDMI 1.3 removed the restrictions on overshoot which prevented the use of pre-emphasis (signal amplification) on source components. Now, sources can improve performance at higher speeds and when using longer cables. As it turns out, most manufacturers are doing exactly this on newer released devices, making long HDMI runs far more achievable than before… Hooray!

So vitally, what is important for the consumer to consider before making their long HDMI cable purchase decision?

Of course, cable quality and construction are always important considerations for any cable purchase decision, but especially more so for long distances. The key thing to look out for is that the cable is designed to pass Category 2 specifications for the long cable lengths. Some cables will boast a Cat2 spec, but in reality that may only apply to the shorter cable lengths in that range. So it is a good idea to confirm for definite with the manufacturer or retailer the exact cable specs at the metre length you intend on purchasing. Installing an inferior spec HDMI cable in your ceiling or wall that is only designed to pass Category 1 (742.5 Mbit/s) would be a gross error, it will definitely not be future-proof and to assume that it would be just fine for features such as 1080p and 12-bit Deep Colour would be extremely naive.

For exactly these reasons, ALL of our cable ranges up to 15m have passed the (cat2) speed-rating test. We use 24 AWG rated cabling in all our cables over 5 metre in length, to ensure faultless signal transfer even over these long lengths. You can have peace of mind that a hdcable.co.uk product will provide rock –steady performance at 1080p 12-bit deep colour, guaranteed.

What we offer as a solution for long HDMI cable runs:

For distances up to 15m you can try:

A 15 metre Platinum or Pro-2 range HDMI cable will comfortably support 1080p with Multi-channel 5.1 Audio.

For distances 15 – 25m

A good solution at this distance is to use two cables joined together to make a longer cable using a HDMI extender/repeater unit. This will ensure that the best signal integrity is maintained from source device to display.

For distances over 25m

We recommend using our 35m HDMI Extender Cable for this distance. The in-built amplifier repeater element within the cable enables super reliable full HD 1080p signal performance even over this long distance and meets HDMI Version 1.3 CAT2 specifications.

For distances over 35m

It is possible to daisy chain HDMI cables using HDMI extender/repeater units. However this is not the most cost effective method for running a HD signal over distances of 35m. For distances over 35m we recommend using a HDMI over CAT5 solution. Extend a HD signal over super long distances via the use of CAT5e or CAT6 network cabling. Send a 1080p signal over 60 metres or a 1080i signal 120 metres reliably and effectively using our HDMI super extender over CAT5e/CAT6 balun kit.

Compared to HDMI cabling, CAT-5e/6 cabling is much easier to work with in big installations, being easily bendable, far more flexible and easier to be pulled through inner wall trunking or tubing. High quality, superior shielded professional CAT5e cabling can be purchased from us on 305 metre reels.