Hmmm.... is there such a thing as overpriced HDMI cables?

[Chris D]

(cables are a sensitive topic here, so we'll keep this confined to HDMI topic)
Still wondering if there are overpriced HDMI cables out there?

http://www.cnn.com/2012/06/01/tech/s...html?hpt=hp_c2

[mjb]

Amazon has a nice one, only $2,694.75, and in stock:

http://www.amazon.com/Diamond-Digital-Audio-Ethernet-Connection/dp/B003CT2A6I/ref=cm_cr_pr_product_top

[impala454]

edit: Sorry Chris I just realized I went way outside the HDMI topic ops:

[Dmantis]

Yes there is.

What has to be understood is achieving a goal. With HDMI length and quality goes hand and hand. Also properly build cables will perform better then cables of less quality.

I'm not against spending good money for good quality cables , actually I encourage it but once you achieve the goal , there is nothing more a higher quality cable can provide.
I think this topic is sensitive because there is so much mystery around this topic. Many times a group of audio / videophiles gets heated when opinions fly. There are groups of people who feel cables make no difference , a group that feels very strongly about what cables goes into ones system and another who have no idea what to do or buy due to all the marketing hype and super high prices for extreme cables. But that alone is an opinion as I maybe able to afford a certain level of things and other may or may not. Some may have limitless funds and most of us have budgets. I guess value really determines if something is worth it or not.

Not talking about this subject I believe is a crime as teaching and sharing our experiences is what forums are all about. But when things get heated which they usually do when it comes to cables needs to be controlled and I believe is worth it because there is so much to be learned about cables especially HDMI as right now it's the most sold/used cable.

One thing we all have to keep in check when discussing cables is attitude. Everyone has different opinions and has a right to it. But if one is bashing another for said opinion I feel doesn't belong here on our forum. Bashing isn't tolerated and should be allowed.

Now if we all can talk about said topic like HDMI , I think we all stand to learn something or at least get a different prospective. I for one have been in the business long before HDMI came out and I have watched our industry make a pretty big mess of it. I have also conducted my own versions of testing HDMI cables and have had some interesting results.

In general no one needs to spend a large some of the system budget on HDMI cables but you have to keep in mind that quality cables will perform better then lesser quality ones. length has a lot to do with it , quality of materials used and terminations is key. Once you have a HDMI cable that can achieve data transfer correctly , can travel in said path without altering the signal or losing it somewhere , there is nothing a higher quality cable can provide. Whats very hard to do is find that cable that can do this correctly.

Being in the business has advantages but still doesn't provide the absolute truth on HDMI cables. I have met with so many wire engineers and heard different opinions on how to get the job done right. I would fully like to have a HDMI thread and really dig deep into this topic .

[madmac]

HDMI.....other than what version it can handle is, by and large a digital cable. With digital, either the signal (1's and zeros) gets there, or it doesn't. Period!!. If the signal gets to the amp or the TV, and something is converted, heard or displayed.....mission accomplished!. No amount of additional money is going to make that signal better.

That being said......$20-40 bucks should get you to that point and get you a decent quality cable. Did I mention to you that my dollar store here now sells a 6ft HDMI cable for 2 bucks ??. I bet it works too!!!.

Now...analog cables are another matter altogether!!

[impala454]

I really hesitate to equate a dollar amount to what makes a quality cable. Long ago I worked at a Best Buy, and cables period (any type) are among the highest markup item in the store (upwards of 2000%). So a $40 cable only cost best buy a few dollars. That, to me doesn't say quality so much as say, an equally priced cable from some reputable online dealer that exclusively deals in cabling.

HDMI is another story as even reputable online companies tend to simply resell cables which are manufactured elsewhere (albeit probably better quality cables anyways). Just an example, blue jeans cable states on their site that their HDMI cables (while some components are sourced in the US) are actually built in China. What I do like is the ability to order a specific length, and get the shortest possible cables for my needs.

[madmac]

I really hesitate to equate a dollar amount to what makes a quality cable. Long ago I worked at a Best Buy, and cables period (any type) are among the highest markup item in the store (upwards of 2000%). So a $40 cable only cost best buy a few dollars. That, to me doesn't say quality so much as say, an equally priced cable from some reputable online dealer that exclusively deals in cabling.

HDMI is another story as even reputable online companies tend to simply resell cables which are manufactured elsewhere (albeit probably better quality cables anyways). Just an example, blue jeans cable states on their site that their HDMI cables (while some components are sourced in the US) are actually built in China. What I do like is the ability to order a specific length, and get the shortest possible cables for my needs.

I agree about the crazy markup thing. That's probably how the dollar store can pop out HDMI cables for 2 bucks. Like I said, any digital cable is ones and zero's and those one's an zero's either get there to the decoder or not. If not, no signal....if yes.....signal. This also applies to Optical as well. :W

That being said, if the dollar store cable works, then it would be indistinguishable from a $100 cable in both picture and sound sadly 8O

[impala454]

Eh it's not that cut and dry though (the no signal/yes signal part). At the lowest level it's still an analog electrical signal. There's not little magical ones and zeros flowing through the cable. Just like the ethernet cable (or wifi) connected to your computer as you read this. It's digital data yes, but the base low level hardware is still an analog signal of some type (unless you have fiber, but even in that case at some point in your computer it gets turned back into electricity).

I do agree with you that if a cable works properly, it won't provide a better quality picture or audio from a fancier cable that also works. But electrical connections can be interrupted whether the high level signal is digital or analog. Which is why we have to put everything we build at NASA into an EMI chamber for testing.

[bigburner]

Still wondering if there are overpriced HDMI cables out there?

The sky's the limit mate. Quality doesn't come cheap.

Nigel.

[madmac]

Eh it's not that cut and dry though (the no signal/yes signal part). At the lowest level it's still an analog electrical signal. There's not little magical ones and zeros flowing through the cable. Just like the ethernet cable (or wifi) connected to your computer as you read this. It's digital data yes, but the base low level hardware is still an analog signal of some type (unless you have fiber, but even in that case at some point in your computer it gets turned back into electricity).

I do agree with you that if a cable works properly, it won't provide a better quality picture or audio from a fancier cable that also works. But electrical connections can be interrupted whether the high level signal is digital or analog. Which is why we have to put everything we build at NASA into an EMI chamber for testing.

I guess you have a point but it's a minor one. The quality from any digital cable will be in it's decoding vastly!!. Per your profile pic, it looks like you've got some bad wiring happening there!!!!! :rofl:

[bigburner]

Yeah, experts reckon that digital is just ones and zeroes but I've heard that with cheap cables those ones can turn into twos and sometimes the zeroes can even turn into threes. Before you know it your Tchaikovsky album is sounding like Snoop Dogg.

Nigel.

[madmac]

Yeah, experts reckon that digital is just ones and zeroes but I've heard that with cheap cables those ones can turn into twos and sometimes the zeroes can even turn into threes. Before you know it your Tchaikovsky album is sounding like Snoop Dogg.

Nigel.

:rofl:

[wkhanna]

With digital, either the signal (1's and zeros) gets there, or it doesn't. Period!!.

This is the biggest misconception there is regarding digital signal.

Please, anyone who puts faith in this platitude, do a little research. The facts are easily found and explained.

The signal must reach a minimum value to be recognized. If anything interferes or gets in the way at the threshold value, the signal is corrupted.

[madmac]

This is the biggest misconception there is regarding digital signal.

Please, anyone who puts faith in this platitude, do a little research. The facts are easily found and explained.

The signal must reach a minimum value to be recognized. If anything interferes or gets in the way at the threshold value, the signal is corrupted.

Yes but........any working cable will reach that minimum value no???

[madmac]

Don't get me wrong folks, I am not using cheap cables....but....I'm also not paying a fortune for them either. I believe in using good cables for my gear......just within reason!!.

[Dmantis]

Don't get me wrong folks, I am not using cheap cables....but....I'm also not paying a fortune for them either. I believe in using good cables for my gear......just within reason!!.

Not everyones reason is the same.

What is a fortune or to much for a HDMI cable to you?
Again I find it a quest to get a cable that can get the job done correctly. At what point does that happen is the real question. If you can achieve the goal 100% correctly then buying a higher priced quality cable can't achieve any better anything correct? You can't Improve on the signal but you can damage it. The actual goal is to send the entire signal from A to B unaltered.
I think the quest here is to figure out maybe by length what it takes to get that done. From what I understand anything under 2 meters is pretty easy to do , once you go over 5 meters is when things get hairy and difficult. then when you have a projector or relocated gear , cables of 10 , 12 , 15 or even 20 meters are necessary. After that your looking are Looking at Balun devices that extend HDMI over cat 5 , coax and RGBHV.

[kgveteran]

I use the $3 on ebay ops:

[madmac]

Not everyones reason is the same.

What is a fortune or to much for a HDMI cable to you?
Again I find it a quest to get a cable that can get the job done correctly. At what point does that happen is the real question. If you can achieve the goal 100% correctly then buying a higher priced quality cable can't achieve any better anything correct? You can't Improve on the signal but you can damage it. The actual goal is to send the entire signal from A to B unaltered.
I think the quest here is to figure out maybe by length what it takes to get that done. From what I understand anything under 2 meters is pretty easy to do , once you go over 5 meters is when things get hairy and difficult. then when you have a projector or relocated gear , cables of 10 , 12 , 15 or even 20 meters are necessary. After that your looking are Looking at Balun devices that extend HDMI over cat 5 , coax and RGBHV.

Absolutely......the longer the run. the better the cable has to be. Period!! :T

[Hdale85]

My 50ft HDMI cable was 25 bucks.....works fantastic and looks awesome at the same time. It's tech flexed and has some really nice connectors. I believe it was 20AWG or 22AWG where as most of the real cheap ones are like 26.

[PewterTA]

Basically with HDMI, a cable is basically a cable... The error correction on each part of the code (video, data, audio, etc) that passes through each has their own Error correction built into the protocol...so as long as the signal can get there... it's there and it's good. Audio though I do think is the "weakest" link on the error correction portion.

So because of this, there's really less about the "quality" of the cable and more can it do the job? Now, I'm one for buying a reasonable quality build of a cable. I've bought all my HDMI cables from BlueJeans as they are a good quality, not expensive and they just work...never had an issue... So really there's not any need to buy super expensive HDMI cables.

*note* I'm not saying this go across all other cables, as I do feel there are differences in other applications of cables.

Here's the specs and shows how much error correction is available (especially on physical and data) for each application.

From 4.2.5 (physical layer):

quote:
For each channel under all operating conditions specified in this section the following conditions
shall be met. At TMDS clock frequencies less than or equal to 165MHz, the Sink shall recover
data at a TMDS character error rate of 10-9 or better, when presented with any signal compliant to
the eye diagram of Figure 4-20. At TMDS clock frequencies above 165MHz, the Sink shall
recover data on each channel at a TMDS character error rate of 10-9 or better, when presented
with any signal compliant to the eye diagram of Figure 4-20 after application of the Reference
Cable Equalizer.


From 5.2.3 ("data" coding, basically everything that isn't video or a control signal -- audio, content protection, gamut metadata, etc.):

quote:
During the Data Island, each of the three TMDS channels transmits a series of 10-bit characters
encoded from a 4-bit input word, using TMDS Error Reduction Coding (TERC4). TERC4
significantly reduces the error rate on the link by choosing only 10-bit codes with high inherent
error avoidance.
... ...
All data within a Data Island is contained within 32 clock Packets. Packets consist of a Packet
Header, a Packet Body (consisting of four Subpackets), and associated error correction bits.
Each Subpacket includes 56 bits of data and is protected by an additional 8 bits of BCH ECC
parity bits.
... ...
To improve the reliability of the data and to improve the detection of bad data, Error Correction
Code (ECC) parity is added to each packet. BCH(64,56) and BCH(32,24) are generated by the
polynomial G(x) shown in Figure 5-5.


From 5.4.4 (video coding):

quote:
During video data, where each 10-bit character represents 8 bits of pixel data, the encoded
characters provide an approximate DC balance as well as a reduction in the number of transitions
in the data stream. The encode process for the active data period can be viewed in two stages.
The first stage produces a transition-minimized 9-bit code word from the input 8 bits. The second
stage produces a 10-bit code word, the finished TMDS character, which will manage the overall
DC balance of the transmitted stream of characters.

(this isn't error correction per se -- it's an attempt to minimize problems @ the physical layer)

From 7.7 (audio):

quote:
The behavior of the Sink after detecting an error is implementation-dependent. However, Sinks
should be designed to prevent loud spurious noises from being generated due to errors. Sample
repetition and interpolation are well known concealment techniques and are recommended.

[wkhanna]

The Curmudgeon’s 3rd Rule of Correlations:

Analog vs Digital = Man vs Woman

[madmac]

The Curmudgeon’s 3rd Rule of Correlations:

Analog vs Digital = Man vs Woman

Look at all the controls on the woman's unit!. She can do so much more!! :T

[PewterTA]

....and imagine if just one of those controls is not set right....................

[wkhanna]

Afer reading Dan's post pointing out the specs of error correction, my intent was not to imply Analog is necessarily better, only that the technology required to approach the same level of accuracy with Digital is at times mind boggling (at least to me).

I was reminded of an early 90’s editorial from one of the engineering trade magazines I get at work. The article questioned the rational of spending billions (think trillions in today’s $) on projects such as the space shuttle, pointing out the first tragedy resulting from the seal failure of the solid rocket booster, and the imperfections on one of the Hubble Telescope’s original mirrors.

The basic thesis being offered was that the uber complexities of such systems along with the requisite redundant sub-systems were statistically inherent to likely failure. Thus making such endeavors economically unsound. Not to mention the risk of loss to human life.

Originally and in retrospect, I personally feel that the cost, risk, tragic losses & system failures are far outweighed by the return on investment. The innate character of man is to pursue the impossible in full acceptance of the consequences of failure. It is what we do. It is what makes us who we are. The gains in knowledge & the resulting spin-off technology are immensely responsible for advances in everything from the medical field to I-Pads.

We are pioneers. We accept the risk. And some day, we may even make it possible for Digital music to sound as good as Analog at a cost that is far cheaper than an equivalent Analog system. :W

[bigburner]

And some day, we may even make it possible for Digital music to sound as good as Analog at a cost that is far cheaper than an equivalent Analog system. :W

Bill, that day will be when surgeons can provide aging people with new and improved ears so they can appreciate the superior sound that modern digital systems provide!

Nigel.

[Johnloudb]

Well, not just 1's and 0's ... 1's and 0's traveling through space and time.

HDMI cables do make a difference, cause timing information is also transfered via the HDMI cable which induces jitter. Also the audio samples are spread farther apart with HDMI because it's sending video information as well, and this makes timing errors greater, than say with SPDIF connections. These errors cause signal non-linearity, distortion.

Also found this I this explanation (post #12) on the AVS forum which I though was a good one:

http://www.avsforum.com/t/1296730/is-hdmi-asynchronous-does-clock-jitter-matter

Quote:
Sorry to say, but I don't trust most audiophiles when it comes to digital gear. I have worked with and designed digital gear and synchronous communication, and I understand that it is entirely possible to eliminate jitter at a given stage by simply storing the information in memory. That is why I'm puzzled that there should be any jitter whatsoever introduced into the DAC by the transport.


As one engineer to another, let me say there is more to the story than part of the chain which ended above .

Quote: Now, I understand it's completely possible if the protocol was badly designed, and that very well may be the case. I'd like some clarification here, because as I have worked in the field, I haven't worked specifically with HDMI or SPDIF.

As a digital transport, nothing is wrong with either. Well, I take that back. HDMI sucks at that also but that is for another topic, unrelated to jitter and fidelity .

Quote: Now, back on topic...since HDMI has error correction, it needs a buffer on the receiving end. As such, I can't see the jitter from the sending device being preserved, since I assume an ECC buffer would need to be random accessible, and not FIFO (unless it's FIFO + addressible, I guess). This is, again, purely assumption, but I assume that the data is stored in the buffer, and essentially retransmitted to the device's processor at that point.

All correct. Let's make this very simple and assume that all digital data is extracted from the link perfectly. You now have audio samples (or bit stream from the compressed audio) ready to be played.

What happens next? As you know, a DAC requires a clock. Where do you get that clock? You have two choices:

1. Use any old oscillator. You take the sampling rate of the source and enable the clock at that frequency. Well, this won't work! Why? Because the sampling rate is the nominal value of the audio samples, not actual. When content is encoded for example, one could choose to put out 47,999 samples/sec instead of 48,000 and still be correct. If you clock the audio one sample faster than the source, over time you drift and pretty soon, the audio is no longer in sync with video.

2. Derive a clock from the HDMI source. You use a PLL and lock your frequency to the source. This gives you the correct data rate since you now are in sync with the incoming samples. But now, you have a performance issue. The HDMI clock is designed typically to be good enough for you to recover the data samples. Once there, designers think they are finished. Yet, we now need a very high precision clock to drive the DAC.

How precise? For 16-bit audio at 20 KHz, you need to achieve 500 picoseconds accuracy or you lose the low order bit. That will be challenging to maintain in a typical system. You have HDMI clock itself varying to some extent due to clock instability, cable induced jitter, etc. You have interferences inside the receiver which cause cause their own jitter.

There are solutions to this problem of course but they get complex and expensive since you only want to filter the jitter, but not true changes in source rate. Some use double-PLL circuits. Others use proprietary techniques.

To avoid the next phase of this discussion and what makes people frustrated with these arguments , let's avoid talking about what is audible and what is not. Instead, let's agree that audio reproduction is part digital, part analog. Audio samples are digital in value. Timing of the samples is an analog event which must be in sync with the source. And to add insult to injury, we have high precision sample values which mean jitter has to be quite small for transparent reproduction.

Hope this gives you an overview. Now you are armed to do the above search and read through the rest of the arguments.

[wkhanna]

Ah crap. Wouldn’t you know it!
Someone who actually knows what the hell they are talking about comes by and ruins all the fun. :W

[Johnloudb]

Ah crap. Wouldn’t you know it!
Someone who actually knows what the hell they are talking about comes by and ruins all the fun. :W

LOL, I'm sorry Bill. Learning is kind of fun too though huh.

[bigburner]

Ah crap. Wouldn’t you know it!
Someone who actually knows what the hell they are talking about comes by and ruins all the fun. :W

Don't be fooled by John's technobabble Bill. We use it all the time in the computer industry to mask our ignorance!

Nigel.

[Johnloudb]

Don't be fooled by John's technobabble Bill. We use it all the time in the computer industry to mask our ignorance!

Nigel.

Nigel, if you have better information maybe you'd like to share? I don't want to live in ignorance.


John

[Johnloudb]

Well, here is a paper on the HDMI 1.3 specification:

https://engineering.purdue.edu/477grp10/Datasheets/CEC_HDMI_Specification.pdf

The specification shows 3 data channels and a clock channel sent via a balanced connection, and well as some other control channels. The audio data is sent in what they call data islands that contain audio sample packets. And the clock ultimately affects when the packet is released.

Anyway, I have no problem with what I said. My opinion has not changed, but lets keep the discussion going. Would love to hear alternative view points. :T

[madmac]

Well....If it plays, has audio and displays a clear picture.....we're done!! Thank you!!

[wkhanna]

John, knowing Nigel as I do, I must believe his intent was simply to poke a little fun at me and not question the validity of your previous post. It is an unfortunate but common consequence of the medium & satire can often be misconstrued in this format

[PewterTA]

The thing is... it's not the cable that's causing most of the jitter issues, it's the HDMI protocol itself that's more the problem than any cable would even hope to induce....

I stole this and it's a nice easy interpretation of what's wrong with HDMI as a transport more so than any issues with cables.

"There's a fundamental difference in the way that spdif and HDMI handle digital audio, and unfortunately it seems to cause more of a problem with HDMI. Most audio systems screw up digital audio in one way or another, but HDMI adds a new way to do it - plus a possible way out. Digital audio carries not one, but two, information streams - amplitude information and timing information. The amplitude info is the data in the ones and zeros, and the timing info is the synchronisation between the sampling (ADC) and the reconstruction (DAC) of the analogue output stream.

SPDIF carries both streams on the same channel - the timing info is embedded into the data stream, which are recovered and separated by the receiver for sending to the DACs. Sources and sinks have gotten better over the years, but as you might expect, this is a compromise, and the data tends to corrupt the timing.

HDMI does it quite differently, and carries data (amplitude info) and clock (timing info) on physically separate channels. Although the audio data is embedded into the video data on HDMI, this is still a good thing in principle, as it should help to maintain the integrity of the clock. Unfortunately (and this is why audiophile manufacturers criticise audio on HDMI) the HDMI clock is a video clock, not an audio clock. The receiver has to reconstruct an audio clock out of the video clock by down-sampling it internally under continuously varying decimation commands sent over the CEC by the transport. This DOES work (well... function) but nothing like as well as a dedicated audio clock.

Hence the problem with HDMI audio, and it is a real problem, nomatter what some manufacturers may say. Its not a simple matter though. HDMI seems to perform much worse when there is no video being carried. Playing a CD over an HDMI connection can be very poor, and spdif can sound significantly better. The difference can only be attributed to jitter on HDMI - either because of the link, or because of the receiver processing. LPCM with video on HDMI seems to be a different matter though, and can sound very good. I have a good understanding of the causes and effects of jitter, but things start to get difficult here. I think that audio jitter may be related to the video clock that is used for each signal transmission format. HDMI has a very wide range of transmission formats, which have to cover everything from NTSC to 1200p video. There is a correspondingly very wide range of video clock frequencies to cover these, and some of them don't seem to work well with audio. CD audio seems to be a particular problem, but HDMI does have a trick up its sleeve to get round this very effectively, and I'll come back to that later."

[Johnloudb]

Hi Dan, thanks for posting that.

Where did you get that from? I agree with him that having a separate clock signal is helpful.

A lot of what he says doesn't make sense to me though. Like him saying that LPCM with video sounds very good but CD sounds bad. It shouldn't make any difference. If the clock works well with the sampling rate of LPCM then it should work well with the sampling rate of CD. Also, the NTSC standard is an analog TV signal and not digital like 1080p. And do they really change the clock rate to work with different video formats? I don't see why they would, but I don't really know.

Of course to really know what the problem is you'd have to do some measurements of the jitter, like some people who design the equipment do.

The HDMI cable is really complicated with many shielded wires wrapped up in a specific geometry. A lot could go wrong if it's not designed or manufactured well. There could be problems with interference, impedance mismatch, dielectric absorption, etc ... that could be improved upon in a higher end cable.

Anyway, I am certainly no expert on video formats or HDMI. All I had was the HDMI specification sheet which all of a sudden disappeared off Purdue's website. I guess they didn't like me looking at it.

I'm just saying the cables make a difference with jitter, which does have an effect on distortion. There could be problems related to the format as well that cause jitter, like you say.

John

[bigburner]

Nigel, if you have better information maybe you'd like to share? I don't want to live in ignorance.


John

It was a poor attempt at humour John. Apologies.

Nigel.

[bigburner]

John, knowing Nigel as I do, I must believe his intent was simply to poke a little fun at me and not question the validity of your previous post. It is an unfortunate but common consequence of the medium & satire can often be misconstrued in this format

That's 100% correct Bill.

Nigel.

[Johnloudb]

It was a poor attempt at humour John. Apologies.

Nigel.

I understand, the same has happen to me. Easy to get taken the wrong way on message boards.

John

[Lex]

Dan, of course, you are right, talking about the heated nature of cable debates. We've all seen them, and no one can ever be wrong, thus we have the great debate among pro cable users and a cable is a cable group. I don't think this will ever change. It's always going to be a hot topic.

There are however positive benefits to quality cables, we all know that as well. But there is a point of diminishing returns. I believe 2600 for an HDMI cable is well past that point for me personally. However, there are people that this is a drop in the bucket too, and if there's a chance it will make a difference, they don't mind spending it. I will say there are probably not to many in that group nowadays. But a few anyway. I don't begrudge them. They hopefully have eliminated chance as a bad variable in their system by dotting their I's and crossing their T's. Whether it makes a difference or not is in the eye of the beholder. Of course, there can be pseudo differences they see as well, when spending that kind of money, they want to see a difference, and usually do. Blind test? Let's just not go down that road here.

[Audio bliss]

hdmi mayhem!

Aahhh...the HDMI debate....well all I can say is...I did a 3 month test of different cables ranging in price of 45-100$ and all of them looked and sounded slightly different from one another...0 and 1s they may be...but I'm a very critical listener & watcher...the 100$ big name brand got smoked by a 50$ one on sound,detail,and sharpness...mostly in the sound....but I did find one that ...to me was perfect in sound depth and HD picture quality so now I have 3 of those running thru my rig...at 110$ each..there worth every penny!.....straight wire!....audio quest a very close second!