Want a free HDMI cable? Buy a telly from either John Lewis or Currys and you'll get one - not from those retailers but from upstart Aussie e-tailer Kogan. The online store claimed "some retailers have decided that it’s appropriate to trick unsuspecting UK shoppers into thinking a £100 HDMI cable is better than a £4 one", so it's …
Paying not with cash...
... but potentially with personal data:
"The Promoter may, for an indefinite period, unless otherwise advised, use the information for promotional, marketing, publicity, research and profiling purposes, including sending electronic messages or telephoning the claimant." (clause 15)
It should, of course, be easy to unsubscribe, and exchanging personal data for a £4 cable may seem a fair deal for those rich in data and poor in wires .
It's always made me laugh. A digital signal is either received or not received, as I'm all too aware when it's pissing down on our exposed sat dish. paying £100+ for a HDMI cable is the modern equivalent of being gulled by a snake oil seller.
The only downside of cheapo cables are their propensity to fall to bits, which puts them in the not receiving category imho.
Common schoolboy error
It's never as simple 'received or not recieved': digital transmission formats have error correction systems built in to them, to deal with data that doesn't get through. In addition to these, the data encoding schemes will be designed to cover up a percentage of 'permanently lost' bits, but eventually it gets to a point where the lost data can't be covered up, and you get skipping on your CD, or artifacts on your DVD, or Freeview broadcast, or breakups on DAB, etc.
No Error Correction
Can we just clear something up once and for all. There is no error correction ( should I put that in capitals ? ) on HDMI. None , nothing , nada.... this is one way raw data transfer there is no error detection let alone error correction. If digital was all it took for your ' it either works or it doesn't' approach then why do we have error correction on network comms , clearly they 'shouldn't need it' after they are 'digital'.
Common sense should lead us to conclude that in the absence of error correction, the only defence against data corruption is cable assembly and cable components , both of which are likely to escalate in cost the more attention is given to them.
What is in the favour of those who advocate cheap cable is that most people only need a 1m cable and over those distances data loss is likely to be minimal, however in cable world length is not the only issue since most problems arise at the junction points i.e. the plug and the socket and the plug and the cable.
Clearly there is a law of diminishing returns here, I doubt a £20 cable is going to be twice as good as a £10 cable , but I don't have any difficulty believeing that it is a better cable and if I choose to by it on that basis then surely I should be entitled to do so without being called an idiot.
"No Error Correction" "one way" "raw"
Data and audio use an 8 bit BCH parity word in each 32 bit packet header and in each 64 bit subpacket.
It has a two way I2C-ish control channel.
And the video data is 10/8 TMDS encoded.
"should I put that in capitals ?"
You can write it in 48 point magenta comic sans if you like ... it'll still be bollocks.
It works or it doesn't?
So you buy the £10 cable, try it out. If it doesn't work you return it and buy the £20 one? Net loss £0 net gain possibly £10?
Or if you are in the shop, get them to test it there and then.
Yeah, you might have made an extra special trip, just to buy a cable so the fuel costs could outweigh the risk but who would drive a long way just for a cable?
Anyway, the story is about a £4 versus £100 cable - both of which are usually no more than a couple of metres.
I've also bought hundreds of short HDMI cables all at less than £3 and none of them have ever had problems, despite some of them being regularly pulled in and out.
All us AV afficionados know that the picture and sound quality is much better the more you spend on a cable, stands to reason dunnit *sniff*
Let me explain for those mere mortals who don't understand how the price of a cable affects the signal quality.
It's the comissionaire effect.
When you buy a fancy aligned crystal N2 treated gold/rhodium plated cable the riff raff noise signals see the fancy gold and expensive price tag then don't dare enter as they're intimidated by the expensive appearance and all that gold piping on the shoulders of the plugs, they prefer a cheaper Lidl/Aldi cable as it's more in keeping with their social standing, thereby allowing more of the pure, clean cultured cogniscenti signals to enter and enhance the profit margins of the retailer...
I've bought dozens of dirt cheap 15 (yes, fifteen) metre HDMI cables from CPC to connect screens for exhibition and shop display use, the only time I've had a problem with one is when some muppet has run over one or damaged the connectors in some way. the picture quality is utterly indistinguishable between the <20quid ones and the hugely expensive ones recommended by the 'display solution' vendor. Sure, perhaps with 50k of test equipment I might be able to show a minor difference but I doubt it'd be significant and certainly not worth the mark up on the cables.
By all means go and get your wallet raped by a retailer if it makes you feel better (I'm going to call you an idiot though) but from experience I *know* that there's no difference other than price, plus I can afford to carry half a dozen of the cheap cables as spares for when some twat loses/steals or destroys a cable an hour before an exhbition opens doors.
If you are really interested you should read this.
I have been using a 15m £20 HDMI cable for a couple of years now on my projector and it will happily display 1080p...
BCH parity applies only to the Data Island Period not the Video Data Period. The data island period is involved with audio and control only.
Video data uses 8b/10b encoding , but that is to control signal skew and has nothing to do with error correction.
True error correction would require bi-directional control signals , packet retransmission , buffering etc none of this happens when you send data over an HDMI cable.
Can we please stop confusing digital data transmission over hdmi with digital data transmission using an error corrected networking protocol.
Stop digging, Doug 14.
Your original statement was "There is no error correction ( should I put that in capitals ? ) on HDMI. None , nothing , nada". This was bollocks and remains bollocks.
"True error correction would require bi-directional control signals"
This is more bollocks. Forward error correction schemes don't require a back channel. You encode the data with 'spare' information that can be used to spot and/or correct transmission errors.
I've been arguing this for months and months... there is exactly *no* reason why a three hundred quid cable will work any better over a three quid one, if the three quid one meets the specs.
As Kogan says - it works, or it doesn't.
I blame the audiophools, who seem to have infected the population as a whole. I don't blame the manufacturers who are well aware of the old saw about a phool and his money...
A digital signal is a series of bits either signifying on or off. The world unfortunately isn't digital and still suffers from nasty analogueness which means that the standard way to determine if a "bit" is on or off is to set a threshold for the analogue value - over that setting, it's a 1 and below it's a 0 (in some systems the meaning is reversed but that's just semantics)
Cables are not perfect and neither are the components converting from analogue to digital. So the cables can cause problems around a range of analogue signal values which can be misinterpreted by the receiver as the wrong binary value.
Ultimately, this can translate to corrupt images portions or temporary sound dropout that doesn't affect the entire stream and not necessarily consistently.
This "it either works or it doesn't" is a vast simplification of an extremely complex situation or shows a lack of understanding of basic signal engineering.
In the world of audio, the law of diminishing returns certainly applies but the purer the copper in the wiring, the better the signal at the receiver (in the case of audio, the speakers.) If you're speakers aren't up to the job or your amp blows, all bets are off of course.
A more expensive cable can and usually does give a better reproduction of the original recording as long as the expense is due to improved component make-up and not on the usual "name" premium.
As you pour more money into the cable, the signal improvement tends towards 0 so for most people, it's a compromise between stupid money and good signal.
Better reproduction? that's a very confusing way of putting it. That suggests one cable would produce a better image than another, but the one which is producing the inferior result will be faulty as it is producing errors.
I would say a better cable reduces the chances of getting errors, but I suspect errors are very few and far between.
All you need to do is get the signal into the TV without errors. An average HDMI cable will do that no problem.
Why spend a fortune on high cables when the internal cabling of the TV is much much cheaper and works perfectly fine.
But nevertheless, my £6.99 Currys Essentials hdmi cable gives me a perfect picture, as does the £2.50 one I picked up at a computer fair. A £120 Monster hdmi cable would give me an equally perfect picture.
While the situation certainly is more complex than "it works or it doesn't", in practice, the margin of the degradation of a digital stream that produces results between "perfect" (no error correction needed) and "unacceptable" (error correction can no longer compensate) is exceedingly narrow.
If your cheap cable can transfer the data such that no error correction is required, then you will gain no benefit whatsoever by buying an expensive cable.
While a high quality cable may provide error free transmission over, say, 10m, while a cheap one cannot, if you only need a 2m cable then both will provide error free transmission and the £70 cable offers no benefit over the cheapie.
@AC, re eh no...
Agree that it's not a simple as some posters are thinking. I suspect the improvement in single vs. increase in expenditure tends to zero very rapidly, though.
Picture this: many years ago wandering around major audio event, browsing a high-end kit builder's stand. Notice interconnect cable to speakers on the demo system, an unusual colour for audio cables. Collar engineer type on stand and to paraphrase;
"That bright orange cable. Is it what I think it is?"
"What, 13 amp mains flex? Yeah. Works a treat..."
So £stupid/metre for homeopathic ley-line aware directional oxygen and intelligence-free cable, or pay just as much as you need to to get the job done... FWIW my HDMI cable runs are mostly short and cheapo 1-2m cables work just fine.
Modern digital cable signalling standards aren't '1's or '0's at all, they're generally some form of differential signalling and some of them are not even binary (ethernet was ternary last time I looked). Furthermore the clock is encoded with the data, so generally, you either receive the signal entact, or you don't.
Sorry, HDMI runs at a maximum clock rate of about 340MHz. Inside that, there's a useful data transfer rate of about half that. That brings it into line with Cat5 cable, which costs about £50 for 305m on a one-off purchase (connectors and crimpers included).
Since then, there is Cat5e (which can handle Gigabit-rates), Cat6, and Cat6a (which can handle up to 10Gb Ethernet and potentially more). And these data rates are at **100m*** (or 50m, in the case of 10GbE), not the paltry interconnect distances between HDMI device. How much is Cat6 cable? About £50 for 305m.
So assuming you bought a 100m HDMI cable, assuming it was running at 1920×1200p60, assuming it has only 8 connectors on it (Cat5/6 only has eight wires inside, HDMI has more than twice that for little reason), assuming the quality of the connectors was better than some manually-crimped RJ45 plug, then it would be worth about £60 (£120 if you doubled all the connectors to make up for missing pins). For a two-metre HDMI cable? I'd expect to pay about 40p/80p - call it pound-store stock by the time you package it. Stick gold-plated (pointless) connectors on it and a bit of quality control and you're into the £5 range. There's zero reason for it to cost any more than that. Ethernet has been surpassing the datarates and requirements of HDMI for decades and in fact if you want to extend HDMI, you're expected to use CAT6-convertors/extenders for it.
There isn't nothing "special" in even the most expensive HDMI cable. Either something meets the HDMI specifications and can carry the logo, or it doesn't and can't - if it meets the specifications and is undamaged you will get a perfect digital image. There might be quality issues in terms of production (e.g. connectors falling off, conductors not taking kindly to right-angles and kinks, etc.) but in electrical terms HDMI cable is surpassed by the stuff that joins your printer to your wireless router (or whatever).
Even the analogue audio-cable scam was absolute rubbish. Digital signals, there's no excuse. I can't remember the last time I saw a packet re-transmit on my Ethernet statistics on any switch or computer I've managed in the last ten years - because it just doesn't happen when you cable and connectors and in spec. And my Ethernet sockets / plugs get more abuse than the average HDMI port - hell, they get plugged in and unplugged every single day into a dozen different devices and still work flawlessly. Unless you're rolling your chair over them, they work. HDMI is no different or more special just because it's carrying audio/video data. If the cable meets the spec, it meets the spec and can do 1920×1200p60, 4096×2160p24, or whatever the relevant spec revision states. If it doesn't meet the spec, it can't be called an HDMI cable.
[puts on snivelling sycophant hat]
I would just like to agree wholeheartedly with Lee Dowling's back-of-envelope sums and general conclusions. These days there is practically no such thing as an uncorrected error when sending digital signals over short-ish lengths of cable.
Glitches can still happen - reading from storage isn't infallible, terrestrial and satellite signals can be rubbish, transcoders can get their knickers in a twist - but cables should be waaay down the bottom of your list of concerns.
'If the cable meets the spec, it meets the spec and can do 1920×1200p60, 4096×2160p24, or whatever the relevant spec revision states. If it doesn't meet the spec, it can't be called an HDMI cable.'
Thank you! A £120 cable will be better than a bit of string, but a bit so string isn't an HDMI cable.
BTW, I've read people claiming that special SATA cables can improve the quality of MP3 files!
"It's a little wrong to say a tomato is a vegetable; it's a lot wrong to say it's a suspension bridge."
I cant speak for HDMI, but I can speak for ADSL broadband. I have seen faster syncs on 10m High quality RJ11 cables than ISP supplied 2m RJ11 cables. There's more to it that it works, or doesn't - whether its enough to really have any massive effect over a short HDMI cable I'm yet to be convinced.
Also seen mains flex used for...
a long RS232 serial printer cable, but it caused a bunch of confusion when we tried using hardware flow control.
Yep, the one with the D25 breakout box in the pocket.
Different problem. ADSL on the telecoms side is an incredibly "noisy" way to splice a large amount of analogue frequencies into different "digital" channels - it's more an A-D problem than it is digital - the transmission is analog to the local exchange / street cabinet and only there is it converted to a real digital signal. So you're actually arguing analogue performance again, which is a different matter (HDMI is only EVER digital). Think of it being a set of modems that all use super-high frequencies (standard old-fashioned 56K modems only use AUDIBLE frequencies so that phone transmission doesn't interfere). ADSL is a bunch of 20+ modems on different high frequencies and only some of them ever connect at any one time (with splitters to separate out the audible frequencies so you don't get more interference than necessary)
Plus, that RJ11 cable connects to your house phone wiring, shares frequencies with any and all phonelines in your house, connects to 20+ years old cabling to the exchange / cabinet, uses only two pairs at most, is subject to all sorts of homebrew extensions and convenience and - get this - there is no such thing as an "ADSL certified cable" that will give you perfect reception if you use it (mainly because you'd have to plug it in at your local exchange, but also because there's no way you could specify such a thing well enough - and if you did, BT would have to replace every bit of copper in England to correspond to the standard). RJ11 cables (actually, that's the name of the connector) are just analogue cables. Most of the time you can get away with only a single pair inside them being wired. They aren't rated for any particular frequencies or anything, unlike HDMI, Cat5, etc. They are basically a bit of copper. I promise you, you can run a phone line over mains cable, jumper cables from electronic sets, even old headphone cables - I've done it when testing internal telecoms for my employer. You could do it with a set of car jump-start leads if you wanted. You *can't* necessarily do the same with Ethernet / HDMI, and you certainly couldn't sell it as an "Cat5" or "HDMI" certified cable because it does not meet the spec at all. It's an entirely different matter.
But HDMI is still inferior to that cable that plugs into the side of your laptop and has done for the last decade at least.
In principle yes ...
... but we'd note that if the cable is particularly crap, it could degrade the signal to the the point that error correction can't recover it.
Well, in that case, TAKE THE CABLE BACK and get it replaced, it is FAULTY.
No surprise at Curry's, that's prime shit advice and extended warranty territory that. Surprised to see John Lewis accused of it though, they're usually pretty decent, at least in my local one, maybe more dodgers work in ones down south.
That's free enterprise for you though, if the public are stupid enough, you're free to rip them off, whilst under the protection of agencys like the one mentioned.
I've found that my megaexpensive Monster cable produces a much more defined picture and if I was to try to describe it I'd say it was warm and fuller. I'm now putting my fingers in my ears and I'm going to say lalalala and make sure I can't hear you because one step worse than wasting my money on a placebo cable would be admitting I'm dumb enough to get scammed. I'm now going to advocate the cable everywhere I can.
Only very special people
can truly appreciate a very special cable.
That would be like saying a higher quality USB cable results in clearer print outs from your printer.
"Monster cable" warmer picture
Are there separate pins for R G and B in HDMI? Surely not? I would have thought that all image data would be packed into one data stream?
If so, there is no way to get a "warmer" image from an HDMI cable - that would require errors on all bits bumping up the red channel by a certain amount or something like that - statistically impossible.
You either get the pixel transmitted right, or a (probably random) error. The same hue shift for all pixels would never happen.
The reviews for that cable...
Aren't there four screened twisted pair cables like ethernet cable, one TP for red, one for green, one for blue, and one for clock?
But the earlier poster was being sarcastic The signal is coded and digital, these analogue sentiments do not apply.
@alex makes a valid point. *Very* cheap cables can suffer mechanical defects, can be a bit less flexible than you'd like, fit poorly etc. etc.
I've replaced exactly one cable because of this, and just get whatever cable is the right length for about a fiver.
" it's hard to recommend a £100 HDMI cable over one that costs a tenner." Who pays a tenner for one of these?
I certainly don't
Tech retailers have always overcharged for cables. When you make a fiver selling a £200-£500 pound piece of kit, of course you're going to attempt to improve your margin by flogging the punter a cable for £10 or more.
If Kogan can give away cables, they're either charging more for the expensive part of the order (so no sales) or just not making any money (so they'll just go titsup). I don't see how either of these options ultimately helps the consumer.
They're spending £4 per john lewis/curry's consumer who hears about this deal (a low number) in exchange for getting a load of free advertising in the tech industry to people who might actually buy from them ;)
I imagine Kogan aren't really concerned about "helping" the consumer, except for those helpful actions that also result in Kogan getting more business. But then, charging a customer a three figure sum for a cable that has, in technical terms, no advantage over a cable sold for a single figure sum isn't really helpful either. There again, to steal a line from Iain M Banks, the default setting for capitalism is that neither helpfulness and fairness are included.
I would imagine this is a creative exercise in getting extra people onto their mailing list, more than anything else.
I needed and HDMI cable in a hurry the other week - £50 later I was a not very proud owner of a 3m article that was noticeably over-packaged. Thing is, the longest I could find on the day was 3m and I wanted a longer one. Off to ebay I went and found 5m and a 10m examples plus a joiner.
4.99, 5.99 and 1.99 respectively (from memory)
Absolutely fine and even work ok when all joined together!
Currys are the worst for this. They were selling a Belkin HDMI lead for £99.99 that was available on eBuyer for a little over £12.
Whilst we're on the subject, their HD vs. SD demonstration (on two TVs side-by-side) needs some independent investigation as to how they've quite blatantly fiddled the SD signal to look appalling.
Actually, the record I've found walking in to a shop was Richer Sounds.
1m HDMI cable, £119.99.
Was nearly as much as the amp I was buying. Took a photo of it as I was so amazed to see one at that price.
Went down to ASDA and bought three 2m ones for £5 each.
That's not the best part, though, is it?
The best part is that the Special Magic Cable is probably turned out on a yuan/100 meters piece-rate basis, in somewhere like Foxcon City.
Even reading about this forces me to 'focus on my breathing'.
Having seen my parents ripped off by pushing them to buy an absurdly priced HDMI cable when buying their all-in-one BR player set (thank God, I already gave them some UTP cables, or else those would have been 'Monster quality' as well), and being stopped 3 times already by my wife in a shop when in discussion with a sales c*nt ("e's not worth it luv!') it is more then overdue to stop this insanity.
Still It it not against the law to give consumers a choice to overspend, but I just can not blame some people to be overwhelmed by techno-babble and double-speak. The only thing 'we' can do is to spread the word.
At the time of writing
the email address listed in the T&Cs for this offer comes back as non-existant.
I've long thought this.
Oxygen free copper/silver wires and gold connectors are all well and good if you are an anally retentive analogue audio purist running cables over an excessive distance, but in the digital world of 1's and 0's a 40% loss in signal still won't turn a 1 into a 0 or vice versa. Does your motherboard have gold tracks connecting the RAM to the chipset? Nope. Is your Sata of Pata cable oxygen free? Nope. Yet they happily move seriously large volumes of data about in an environment flooded with digital noise - and Pata isn't even screened!
I don't think I have an HDMI cable in my house which cost more than £5, and I defy anyone to tell the difference.
Your motherboard does indeed have gold tracks in it. There is about 1g of gold per motherboard
No they don't. What they do have is gold plating on edge connectors and some connectors.
The tracks on the PCB are made of copper and there's considerably more than 1g of metal on them.
Did I say there was only 1g of metal in the board. No, I said there is about 1g of gold and that is correct. Also I was making it simple as there isn't just gold on the contacts, there is gold in many of the components and on some boards all the exposed copper is plated first with nickel and then with gold so it could be said that there is a gold track all the way from the RAM to the chipset. I do know what know what I am talking about, I was making a simple explanation to somebody who I thought didn't know there was any gold in a motherboard, and I am aware that what I have just typed is not a full correct explanation either before you try to correct me.
I had the same sort of "discussion", the frank and open kind, with an audiophile many years ago, when I mentioned that all he was doing was replicating the guitarists distortion perfectly he was so dumb struck that it took him about 3 hours to come back with "but I listen to classical music as well"
re: Fail yourself
Well you wasted your time. I am fully aware that there is gold on the motherboard, but the tracks going from chipset to CPU and memory are not gold plated. IDE cables are not made of oxygen-free organically farmed dodo tail feathers either, just standard tinned copper wire.
Exposed tracks are plated to prevent corrosion on old style edge connectors and such. However 99.9% of the motherboard is not exposed tracks. It is coated. Even the exposed track plating is over the top for normal PC use.
So my point about high-speed digital signals travelling in a high RF interference environment without any need of exotic materials still stands.
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