which hdmi cable?

vertica said:
If you want to get technical, there is no such thing as digital.
The 0/1 idea is a massive simplification, the signal is really made up of two ANALOGUE voltages. As such the signal is subject to exactly the same interference and crosstalk effects that a scart cable would be.
However the effects are far less apparent and tend to mildly distort or blur the '0/1' boundary, but this is generally corrected by the receiving equipment.

For this reason, 90% of the time the cable will make very little difference, but I do have one provided by SkyHD that introduces random bright pixels when passed close to a mains lead - the distortion reaches a level where the error correction essentially makes a guess or interpolates form the surrounding picture.
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All very well put, and I'd add a clarification, that for HDMI, any errors introduced due to a poor quality cable manifest themselves as mentioned above, as 'sparklies' or little tiny brightly coloured pixels in the image, they don't make the image less sharp or introduce distortion or make the colours washed out etc..

The main reason to spend a little more on HDMI is to stop any possible chance of getting these 'sparklies' when some interference is around, in my experience, that's more likely when you start increasing the cable length over 3M as a rough guide.. And even then, £10 spent at the right place will yield a pretty decent 5M cable..
 
Now my head hurts. Analogue voltage?

I can't get my head around how electrical potential difference can be analogue. Or digital.

Can someone explain, in words of few syllables, please? :D
 
Basically the rule to follow IMO is:

Make sure you're buying a cable that has been certified as high speed.

This only really applies for long cables (say >5-10m) so it will definitely play 1080p and 3D content.

It's unlikely, unless you're buying them from the pound shop, that a long cable will fail with 1080p content, but at least by buying a certified one it should just work.

They're still cheap.
 
Snograt said:
Now my head hurts. Analogue voltage?

I can't get my head around how electrical potential difference can be analogue. Or digital.

Can someone explain, in words of few syllables, please? :D
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If you put it in terms of sending an image over a cable,

Analogue just means that every single value of voltage has an effect on the image, so any noise etc that affects the voltage value at any time directly affects the image..

Digital means that effectively you have a threshold value, if the voltage is below it, that is read as a digital '0', and if it's above it, it's read as a digital '1'. i.e. small changes in voltage won't affect the image


For example, take a snapshot of a signal being sent to a TV, at that exact moment the voltage should be 1.0v

In an analogue world, if something causes that voltage to rise to 1.1v (noise etc), then this will change the image being displayed on the TV

In the digital world (assuming a 2.5v threshold), then the voltage rise to 1.1v has no effect whatso-ever, it's still read as a '0' because it's less then 2.5v..

Although I would have thought anyone who knew enough to use the term electrical potential difference wouldn't really know all this.. ;)
 
Pretty sure this picture explains things nicely, Always show it to friends when they ask this question.
HDMi.jpg
 
Demon said:
Although I would have thought anyone who knew enough to use the term electrical potential difference wouldn't really know all this.. ;)
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Thanks for all that info, Demon - I've got one of those wierd brains that picks up snippets of info about every subject possible, but no in-depth understanding of any particular subject :D
 
I'm glad I read similar threads to this before I got my first HDMI kit. I was using a tesco value hdmi cable, and while it worked fine with the PS3, if i wanted to watch TV while the PS3 was on, it disrupted the freeview signal. For convenience, I popped in Morrisons this morning and bought a 2m braided cable for £8 and it's solved the problem.

Definitely wouldn't bother spending any more.
 
I have cables from Amazon, Tesco (Value :D) and a 5m one from OCUK. I also have one that cost about £12-£15, which is hooked up to my PC monitor.

I can't see any difference on screen, but the sleeving on my monitor HDMI lead does look nicer. :D


What I want to see is an image quality comparison for one of those super dooper cables. I'd like a laugh.
 
If HDMI cables are subject to external sources of interference then why when Digital Foundry transmitted the same (still captured) image over 4 separate cables, where the image checksums (hashed) had been calculated before transmission and after transmission they were identical, with no error correction then, they could not have been susceptible to external interference for even one pixel changing would have resulted in a different checksum (hash) from the one transmitted.

These were also randomly selected hashes from the video stream, so there was no change over time. Even the tiniest change in the signal, that was not perceptible to the human eye would have resulted in a different hash

Mushii
 
I have come out with exactly the same comments on HDMI cables until recently.

HDMI cables are certainly not the same quality and do not produce the same results regardless of price under certain circumstances.

I recently went to a AV shop to buy a projector (Epsom TW3500) and needed a cable to run between my av equipment at the front of the room and the projector wall mounted on the rear wall. The estimated length was 16 meters which is pushing it for HDMI without extenders. The shop produced a cable made in Taiwan which was around 100 quid in English money (the demo had been with a shorter cable) and plugged it in. On playing the demo scene I could instantly see that the picture lost some of the colour saturation and sharpness, bushes were more blurred for example, waves didn't have the same sharpness. I asked to try the QED cable which is stupidly expensive and the quality was back to the initial quality with the shorter cable. I am not audio or videophile and in my late 30's my eyesight is not as good as it could be but I could quite easily see a difference between the picture quality. Needless to say, much to the shops surprise as they really were not pushing the more expensive cable, I bought the QED cable. believe me, if the cheaper cable was producing the same quality picture then I would have bought that.

On delivering a projector to my brother-in-law (bought two, one for each of us) we compared my new cable with his 10 quid cable which was around 1.5 meters. Both cables looked more or less the same over the short distance.

I also bought a TV wall bracket from another place which came with a free HDMI cable which looked very nice, shiny expensive looking black mirrored metal plugs and the mesh on the outside of the cable. When trying the cable between my bluray player and my amp (the amp goes to the projector with the QED cable) I got sound and picture loss intermittently. When I changed the cable for another cheapish cable the picture was back to perfect.

From my experiences, I would say buy a cheap cable for short runs. If you need to do long runs then get a good quality cable as you are more likely to notice issues with the picture / sound or use the cat5e/6 -> HDMI extenders / boosters.

RB
 
RimBlock said:
I have come out with exactly the same comments on HDMI cables until recently.

HDMI cables are certainly not the same quality and do not produce the same results regardless of price under certain circumstances.

I recently went to a AV shop to buy a projector (Epsom TW3500) and needed a cable to run between my av equipment at the front of the room and the projector wall mounted on the rear wall. The estimated length was 16 meters which is pushing it for HDMI without extenders. The shop produced a cable made in Taiwan which was around 100 quid in English money (the demo had been with a shorter cable) and plugged it in. On playing the demo scene I could instantly see that the picture lost some of the colour saturation and sharpness, bushes were more blurred for example, waves didn't have the same sharpness. I asked to try the QED cable which is stupidly expensive and the quality was back to the initial quality with the shorter cable. I am not audio or videophile and in my late 30's my eyesight is not as good as it could be but I could quite easily see a difference between the picture quality. Needless to say, much to the shops surprise as they really were not pushing the more expensive cable, I bought the QED cable. believe me, if the cheaper cable was producing the same quality picture then I would have bought that.

On delivering a projector to my brother-in-law (bought two, one for each of us) we compared my new cable with his 10 quid cable which was around 1.5 meters. Both cables looked more or less the same over the short distance.

I also bought a TV wall bracket from another place which came with a free HDMI cable which looked very nice, shiny expensive looking black mirrored metal plugs and the mesh on the outside of the cable. When trying the cable between my bluray player and my amp (the amp goes to the projector with the QED cable) I got sound and picture loss intermittently. When I changed the cable for another cheapish cable the picture was back to perfect.

From my experiences, I would say buy a cheap cable for short runs. If you need to do long runs then get a good quality cable as you are more likely to notice issues with the picture / sound or use the cat5e/6 -> HDMI extenders / boosters.

RB
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Whilst I don't doubt a poorly built cable will struggle over such distances, I don't understand how the differences would manifest themselves in colour saturation/sharpness - surely errors will look like artefacts on the screen, which is going to be the result of a faulty lead, in which case you could just take it back and get another!

Also, £100 for the cheaper cable? I know it's 16m but i wouldn't call £6.25/m particularly cheap for a cable!
 
RimBlock said:
I have come out with exactly the same comments on HDMI cables until recently.

HDMI cables are certainly not the same quality and do not produce the same results regardless of price under certain circumstances.

I recently went to a AV shop to buy a projector (Epsom TW3500) and needed a cable to run between my av equipment at the front of the room and the projector wall mounted on the rear wall. The estimated length was 16 meters which is pushing it for HDMI without extenders. The shop produced a cable made in Taiwan which was around 100 quid in English money (the demo had been with a shorter cable) and plugged it in. On playing the demo scene I could instantly see that the picture lost some of the colour saturation and sharpness, bushes were more blurred for example, waves didn't have the same sharpness. I asked to try the QED cable which is stupidly expensive and the quality was back to the initial quality with the shorter cable. I am not audio or videophile and in my late 30's my eyesight is not as good as it could be but I could quite easily see a difference between the picture quality. Needless to say, much to the shops surprise as they really were not pushing the more expensive cable, I bought the QED cable. believe me, if the cheaper cable was producing the same quality picture then I would have bought that.

On delivering a projector to my brother-in-law (bought two, one for each of us) we compared my new cable with his 10 quid cable which was around 1.5 meters. Both cables looked more or less the same over the short distance.

I also bought a TV wall bracket from another place which came with a free HDMI cable which looked very nice, shiny expensive looking black mirrored metal plugs and the mesh on the outside of the cable. When trying the cable between my bluray player and my amp (the amp goes to the projector with the QED cable) I got sound and picture loss intermittently. When I changed the cable for another cheapish cable the picture was back to perfect.

From my experiences, I would say buy a cheap cable for short runs. If you need to do long runs then get a good quality cable as you are more likely to notice issues with the picture / sound or use the cat5e/6 -> HDMI extenders / boosters.

RB
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You've been completely conned, a website did an analysis recently on just this very topic, using hash checks of images sent over various HDMI cables, from super cheaper ones, to very expensive, and they all produced the same hash value. So these "wonder cables" weren't making the picture better at all.
 
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