HDMI cable experiment

[tvmog]

As I was not convinced that the HDMI cable supplied with my Sky HD box was of the highest quality I decided to try swapping it with the £60 Monster cable I bought to connect up my upscaling DVD player to my 37 inch PX80. The difference was quite startling. The Sky HD picture, which was already excellent, instantly became sharper and more vibrant to the point that I had to turn the brightness down on the TV.

However, the other part of the experiment was not so successful. When I connected up my DVD player using the Sky supplied cable there was no picture at all.

 

[Clare Newsome]

Note lack of replies from normally verbose cable skeptics on this thread - that's right, the ones who insist all HDMI cables are the same, and that the cable that comes with the Sky box is "absolutely fine". Like heck it is... Thanks for sharing, TV Mog.

 

[southdownswolf]

all HDMI cables are the same, you must have a "duff" one supplied by sky ;-)

 

[bf1]

[quote user="tvmog"]

However, the other part of the experiment was not so successful. When I connected up my DVD player using the Sky supplied cable there was no picture at all.

[/quote]

This sounds like a settings issue, check to make sure you have selected the correct AV input and make sure the scart is properly connected.

I have a very good quality scart on my DVD player but the slightest movement of the equipment results in it coming out of the socket.

 

[Andy Clough]

[quote user="bf1"]the slightest movement of the equipment results in it coming out of the socket.[/quote]

Same applies to HDMI cables. I've lost the picture on my Virgin V+ box a couple of times because the HDMI cable has worked slightly loose. Always worth checking it's properly connected.

 

[Anonymous]

[quote user="southdownswolf"]all HDMI cables are the same, you must have a "duff" one supplied by sky ;-)[/quote] you people will never learn!

 

[southdownswolf]

[quote user="sex"][quote user="southdownswolf"]all HDMI cables are the same, you must have a "duff" one supplied by sky ;-)[/quote] you people will never learn![/quote]

....oh dear, I was just seeing if Clare reacted, that's why i ;-)

 

[tvmog]

[quote user="Andy Clough"]

[quote user="bf1"]the slightest movement of the equipment results in it coming out of the socket.[/quote]

Same applies to HDMI cables. I've lost the picture on my Virgin V+ box a couple of times because the HDMI cable has worked slightly loose. Always worth checking it's properly connected.

[/quote]

Indeed. A quick rumage round the back of the DVD revealed the HDMI cable to be loose. DVD picture is restored, but the SKY HD is still better with the more expensive cable

 

[Alec]

So, um, strictly speaking clare was a bit quick of the mark then...?

 

[professorhat]

[quote user="al7478"]So, um, strictly speaking clare was a bit quick of the mark then...? [/quote]

Erm... no!

[quote user="tvmog"]the SKY HD is still better with the more expensive cable[/quote]

 

[Clare Newsome]

[quote user="fr0g"]I agree that the original cable simply wasn't up to scratch. This is one reason I think people get duped into thinking these cables vary in quality, because freebie ones are very often badly made rubbish.

A decent quality £20 HDMI cable will give you identical results to the £60 Monster jobby, and you can have 3.... Might not be as pretty though which may be an issue to some people.[/quote]

I spoke too soon.....

Still fail to see how "freebie" cables are 'rubbish" but everything else is 'identical". Still, i'm sure there's years of extensive comparative testing experience behind such claims

 

[southdownswolf]

as with any product, test it before buying ( I know that is more difficult with cables). Then if you are happy with it, it is the right cable for you, whether it be a budget £20 cable or a £200 Wireworld...

 

[Clare Newsome]

[quote user="southdownswolf"]as with any product, test it before buying ( I know that is more difficult with cables). Then if you are happy with it, it is the right cable for you, whether it be a budget £20 cable or a £200 Wireworld...[/quote]

Which is what we always say.... (though even i'm doubtful about the very pricey stuff.... unless you're talking world-class kit and long-length cable runs)

 

[Clare Newsome]

So, apart from better-quality build, connectors and shielding, what have the Romans - sorry, decent HDMI cables - ever done for us?

 

[Clare Newsome]

Obviously my attempt at Pythonesque humour fell flat there

 

[Anonymous]

[quote user="fr0g"][quote user="Clare Newsome"]
So, apart from better-quality build, connectors and shielding, what have the Romans - sorry, decent HDMI cables - ever done for us?

[/quote]

indeed. Shielding is irrelevant on normal length cables. Build quality can be equally high on a £20 cable, as can connectors.

So a very expensive cable gives us what exactly? (over a solid, chunky, well-made, with good moulded plugs and quality connections) - apart from 'brand kudos'[/quote]

better shielded if near power sources so no interference maybe???????

 

[Alec]

[quote user="professorhat"]
[quote user="al7478"]So, um, strictly speaking clare was a bit quick of the mark then...? [/quote]

Erm... no!

[quote user="tvmog"]the SKY HD is still better with the more expensive cable[/quote]
[/quote]

Quite, but then you remember that Clare just went ahead and assumed the cable was so bad that it wasnt working at all, unlike the next severeal posters. Sorry Clare, nothing personal, but it wasnt "that" bad, and that shouldntve been your first thought.

 

[Clare Newsome]

No, I didn't assume - or indeed state - it was so bad it wasn't working at all. Just that it was very poor - we have, after all, come into contact with a large array of freebie cables of this type.

Poor-quality cables have rubbish connectors that too easily become disconnected (not that any HDMI cables are great on this front), and/or often suffer more compatibility/HDMI handshake issues than better-quality designs.

 

[Anonymous]

Very cheap HDMI cables can suffer from quite a lot of cross talk which can affect quality quite a bit. Some also don't have the correct resistance. More expensive cables (and I am talking most things above £15) should give fairly similar quality, at least over short runs. Excessively expensive cables (over about £50) shouldnt offer any real improvement, at least not the ones I have seen. As long as the bit stream makes it through relatively intact, quality should be the same. There is in built error correction which should sort out most errors.

 

[Alec]

[quote user="Clare Newsome"]
No, I didn't assume - or indeed state - it was so bad it wasn't working at all. Just that it was very poor - we have, after all, come into contact with a large array of freebie cables of this type.

Poor-quality cables have rubbish connectors that too easily become disconnected (not that any HDMI cables are great on this front), and/or often suffer more compatibility/HDMI handshake issues than better-quality designs.

[/quote]

And once more i have shot me mouth off before re-reading - which ive just done. Please accept my humble apologies.

 

[Clare Newsome]

I'll forgive you - anything cable-related has to allow for some leeway

 

[professorhat]

[quote user="rigadig"]There is in built error correction which should sort out most errors.[/quote]

Interesting you should say this as I think this is where the improvement comes from... if there is error correction going on due to lost signal, due to interference, then this could well degrade picture / sound quality. Hence a more expensive cable which reduces the signal loss, thus less error correction, gives a better picture. I think you're right, as the price goes up, you're talking the law of diminishing returns, so spending more than £50-£80 sees very little improvement (if any at all dependent on the source).

EDIT - I'm keeping my mouth stumm on this subject now as I realise I might just have invited another flame war!

 

[Anonymous]

[quote user="professorhat"]Hence a more expensive cable which reduces the signal loss, thus less error correction, gives a better picture[/quote]

Since there are error correction bits in the stream, basically providing redundancy, even if there are occaisional errors in the bit stream, the recieving equipment can detect and correct the errors very easily. This wil be dealt with separately from any of the display and picture processing, and is basically transparent. The bit stream should be corrected in real time and be bit for bit correct, and therefore picture and sound should be exactly as intended.

Where this breaks down is when you get multiple errors very close together in the data (within the same error checking block). in this case even the error correction bits can't acurately restore the stream to be bit for bit correct.

What I meant before was that in practice, multiple errors close enough together to be able to foil the error correction and result in a noticeable difference in picture/sound only really occur on very cheap digital cables which are not really up to spec in terms of shielding and resistance. As soon as you have a cable which is up to spec with apropriate shielding (usually only about £15), the stream should be relatively error free over short distances, and the few errors that do occur should be far enough apart so that the error correction can fix it without any loss in quality. Spending more on a cable may well result in less errors in the bit stream (though I suspect there is very little difference over short lengths), however due to the protection that the error correction in the recieving equipment offers, the actual data that gets fed into the display or picture processor should be the same between a £15 and £60 digital cable 99% of the time. This is the advantage of digital. Remember error correction is not interpolation, it results in recovery of the original data.

Longer cable runs are a different story however, and more expensive cables can definitely make a difference there.