Regarding audio: Any difference in using expensive HDMI cables?

Hi Jim, I think Mr Miller needs to take another look at the HDMI spec.

There are no "audio wires" in HDMI. Except for the "Audio Reverse Channel" (ARC), the audio flows on the same three pairs of wires that the video flows on, but is transmitted during the video-retrace periods.

Besides that, audio on HDMI is all digital - the only way it sounds different is when it is broken.

One word: digital.

HDMI is a digital interface which means that its basic orientation is to either work or not work.

There are some theoretically possible fine points related to jitter, but at this point we have no reliable evidence that anybody has ever actually experienced it.

Most efforts related to jitter in HDMI cable again relate to the thing either working or not working and are not to do with any fine points related to audio sound quality.

I have seen some marginal situations where a HDMI link cut in and out or occasionally, dropped bits and there were blocks of noise on the screen and/or there were drop outs or ticks and pops in the sound.

But, this is all pretty obvious stuff.

There is no way that a HDMI cable can affect the timbre of audio or the color quality of A/V being played over it, for example.

In general the SQ and PQ depend only on the connection being reliable, and the quality of the equipment at each end of the cable.

Yep.

 

It's a sucker tax.  Anyone willing to pay for it, is a sucker.  Plain and simple.

It's all a lie designed to get your money. Don't waste money on snake oil cabling. They all love to throw big words around to obfuscate the facts.

In a just world, Mr. Miller would be making license plates, not cables.

Which I'm sure he would claim improved gas mileage and 0-60 performance of whatever car his plate was attached to

I find glass blowing to be very interesting to watch, but I don't think that hand-blown light bulbs burn brighter or longer. ;-)

I love this part, .... as we know, one can certainly think that they perceive a difference in audio presentation. However, the much less subjective video components are more readily quantifiable.

Granted, AQ makes some high quality products, and they may be scenarios whereby something they sell may actually out-perform a cable in one's system for whatever reason. That doesn't mean their stuff is the $hit, it merely means your cables were junk. any properly designed and built HDMI cable is fine. Price and performance do not correlate.

One's money and efforts are overwhelmingly much better served being spent on optimizing the acoustics and interaction between the loudspeakers and the room.


Good luck

What a hoot! Mr. Miller could have at least used the HDMI jitter rag which does have some technical merit.

"Audio wires versus video wires inside the HDMI cable"?

THE MAN LIED RIGHT TO YOUR FACE!

The only difference I can tell in hdmi cables is the quality of the connector and how it holds into the receptical. I just switched to a cable that has a locking device on the plug to keep it tight and connected to the back of my processor. Perfect Patch is the cable I'm using.

There appear to be a goodly number of locking HDMI cables, which I think is a good thing.

Amazon has SureConnect HDMI cables for pretty reasonable prices.

Mr. Miller should stick to stand up comedy, he clearly knows nothing about cables.

One time, I had a cheap HDMI cable that was slightly affecting video quality. The cable itself was supposedly designed for the correct standard. But the improvement was noticeable when I upgraded to a Blue Jeans Cable HDMI. I suspect it was the connector that was the problem, but that's just a guess.

Oh, and I'm not claiming to have noticed a difference with movies/TV. Rather, there was a clarity difference in text and some graphics when using my HTPC with an LCD TV.

Nonsense. You can get sparkles, streaks of wrong colors, a complete drop out of the picture, but not a difference in clarity.

This requires that digital data be changed in-steam by a passive device, in highly sophisticated ways. You are basically claiming that a cheap passive cable applied something like a Gaussian Blur in real time to a HD graphic that was running at 24 FPS or more.

If you really have such a cable, I'm sure that people like Intel and Adobe would want to hear about it! Fools that they are, they think that it takes high performance mulitcore processors running sophisticated software to accomplish such a wonderful thing!

Call them up! I'm sure that they would pay you the big bucks if you actually found such a thing!
Edited by arnyk - 9/3/12 at 9:12am

Not only that, but the data is scrambled as NRZ coding. This has nothing to do with copy protection. The scrambling of bits is needed to reduce the DC content which makes clock retrieval difficult. When serial data rates get into the 100 mhz+ range, NRZ scrambling is mandatory. The SATA and PCIe busses used in your PC uses a form of NRZ coding. So based on this, any error, even a single LSB will cause complete loss of that word. Hence the sparkle and if severe enough in time it will cause complete clock loss.

In addition HDMI carries HDCP which is a key exchange protocol that further scrambles the data to make decoding the stream via a wire tap almost impossible. So again even a single LSB error will cause a loss of that digital word.

A further issue with HDMI is that it is really a quasi parallel interface. Rather than one single serial stream like SDI and AES/SPDIF, HDMI uses four pairs, RGB+CLOCK.. In this implementation, skew due to differences in the wire pair lengths is a problem at these frequencies. (Not a problem at all with your speaker cables!). This is what kills long cables on HDMI. Not the capacitance or amplitude loss due to too small a wire gauge which many boutique manufactures claim. Then why not use a single multiplexed stream? The only benefit of a parallel stream is the bandwidth required is cut by three in the case of HDMI.

And unlike packet based transmission like the internet and broadcast MPEG, there is very minimal error correction with realtime digital video transmission.

Bottom line no HDMI cable can make blacker blacks, more saturated colors, better 3D experience, etc. You either have errors or you don't. Errors are sparkles and dropouts. Sure, the same old analog parameters such as capacitance degrade the bit stream just as with any analog signal. The difference is the way in which the information is carried by the signal.

A serial digital signal like SDI, HDMI, AES, SPDIF, SATA PCIe, is basically just plain old FM (Frequency Modulation).

I doubt it was a Gaussian Blur. (lol)

I suspect that whatever the problem was that it was affecting True Type anti aliasing, which is why it text clarity improved. I do visual design document work as part of my job. I can pick out visual flaws more so than most people in graphical displays and high dpi printed documents , much like a sound engineer can in recordings. Once I replaced the HDMI cables, then the text had the kind of clarity I get with my desktop PC LCD. Some very subtle signal loss was going on before, whether it was happening between the TV and the receiver connection, or the receiver and the HTPC. Now, this was also not a direct 1080p signal. 1080p would not quite fit on the screen properly, so I dropped the resolution output slightly. So there would have been upconverting signal processing going on by the receiver or TV back to 1080p (not sure how I had it set up; I have a new TV now), which would slightly "blur" any error that was occurring.

Well something was obviously broke and somehow fixed. Did you power the equipment down when you swapped the cables? Even more important, if you put the 'bad' cable back does the artifact return?

What you describe cannot be caused by a cable carrying a PCM encoded image. Analog cables, like VGA cables, certainly. But not an HDMI or any other digitally encoded signal.

It actually can . No, it has nothing to do with jitter.

If the E-EDID negotiation fails, the source could send a different resolution signal than the native pixel rate of the display. This in return causes he display to resample (scale) the image to match it to its native resolution, causing high frequency content like text to lose its sharp edges. I have a PC which occasionally does this with identical AVR and display in its output chain. Instead of 1080p, it will transmit 1280x768. The resulting image is soft and has incorrect aspect ratio as a result. I have been too lazy to use our Quantum Data anaylzer to see what is causing that. The fact that it is intermittent points to vagaries of this protocol.

I think the odds are against the cable difference alone causing this but OP's observation sure fit the definition of wrong resolution being sent to the display. As you suggested, it would be useful if he can go back to the broken cable and get the display resolution on the PC and see if it is set differently.

I don't think there is a single thing that is designed right in HDMI . Its application should have remained as short connection to computer monitors and never extended to consumer video applications.

OK, I can agree with that.

I was going to blame EDID as well, but i could not see how EDID would be affected by the cable, unless the wire used by EDID was broken. But then I assumed that the cable would not work at all.

When faced with this type of situation, I prefer to switch the < fill-in-the-blank > back and forth a few times to verify that it isn't something intermittent. If I could reproduce the change every time, then I would feel comfortable blaming the < whatever >.
They took a short-sighted short-cut by copying DVI-D to use as their starting point, and we are now living with the shortcomings that decision has caused, like cables that are too short.

This was a year ago. New TV, old cable thrown away since.

And I realized I made a mistake and wrote True Type instead of Clear Type. When I first got the TV (it was four years ago), I tried adjusting the Clear Type but it would never get that clarity I expected from working with other high resolution displays. That's why I wondered if there was some kind of minor signal degradation that would affect that. Clear Type uses minor coloring in the antialiasing, even for black text on white (admittedly, I don't really understand it LOL). Could it be related to that?

Maybe it will remain a mystery

I agree with your assumption. However, many impementations EDID are not fool proof. It is not the least bit uncommon for EDID to completely fall apart if you connect and disconnect HDMI equipment while it is turned on. Three words: HDMI video switcher.

The point being that its possible for equipment failure (either badly flawed implementation or badly-flawed experiment) to make it appear that different HDMI cables produce different picture rendition. You get misleading results by means of doing a poorly-conditioned experiment. If these comparisons involved the video equivalent of audio level matching, then they would no doubt be far more reliable.

Hi Arny, True. And it probably never will be. Every time you attempt to make something fool-proof, it causes nature to create a better fool.