13
Aug/09
0

The Truth About Monster Cable

Hey guys: I just got back from meeting with Noel Lee from Monster Cable, along with a posse of affiliated ladies and gentlemen, and their heavy equipment. I was there to talk to them about the fact that they sell—and have convinced a lot of retailers to sell—very expensive cable ($120 for 2 meters, last I checked). At the same time, there are cheaper non-Monster cables available on the Internet. My simple question Why? resulted in an organized, technical 2-hour response. I won’t give you the blow-by-blow, but I have information that might make this debate interesting, and a bit more three-dimensional.

Let’s start with my allegation about Monster, which isn’t mine alone, because Lee helpfully pointed out the gist of it in the opening of his presentation:

I say, since everything is digital, and since HDMI is a spec, the cheap cable will get the data from point A to point B as well as any other cable. Additionally I say that if there are subtle (i.e. videophile-grade) differences in cables, the average consumer isn’t going to spot them on the TV.

Am I wrong? Monster says yes, but in Lee’s elaborate answer I felt both his POV and mine were justified.

Here are Monster’s truths:

Bandwidth is King.

 
The requirements of 1080p and beyond is what separates from the high-end cable from the knock-offs. This is the same as Ethernet cable, in the sense that a cable certified for HDMI 1.3a “Highspeed” will guarantee greater throughput. The newest spec, 1.3a means just over 10Gbps of bandwidth. Standard 480p requires less than 1Gbps, the current 8-bit 1080p requires 4.46 Gbps, but the next gen 1080p formats will require nearly 15Gbps, more than the highest certified HDMI cable can support. (See chart if you can, if not I’ll try to get a better one up later.)

Not all cables are the same.


During Lee’s slideshow, he demonstrated via X-Ray slides that pricier cables (OK, Monster’s) have a smaller chance of wear and tear damage at the point where the cable meets the connector. t’s a concept that’s easy for any musician to understand—remember all of those shorting-out patch cords?

Even if it has an HDMI-style connector, it may not be certified HDMI.


You have to look for the HDMI logo, says Steve Venuti of HDMI Licensing. There are tons of knock-offs, especially the bundled or online cables, since you can’t look at the packaging when you buy. Really high-end cables will certify other things, such as HDMI 1.3a and even “Highspeed.”

Just because digital information is made up of ones and zeros it can still degrade, especially over distances.


I get this now, because it’s not about the digital info just getting there, like packet data. It’s video, so it’s about the digital info getting there at the right time to make sense. It’s also audio, and over distances, there’s a greater chance that audio and video will get out of sync. The following pictures show a test that they run that measures data throughput. In the interest of brevity, I’ll just say that the more those lines crowd the center, the greater the risk of having crappy video.

Differences in cable are easily spotted by untrained eyes.


A PS3 feeding 1080p signal to a Samsung 1080p LCD TV starts to jitter and throw digital noise lines across the screen if the cable can’t hack the bandwidth. We tested the two cables above on a PS3 showing a Blu-ray of Chicken Little and it was totally noticeable, there were lines and jitters, none of this videophile matter-of-opinion stuff that I had anticipated. It was totally obvious, and something that Monster says people often blame on their TV, not their cable.

Future proofing and heavy-duty cable are crucial for in-wall installation.


This probably made the most sense of all. Given the fact that in-wall cable is longer than others, you’d need something that can handle the bandwidth. (In fact, when it gets to 50 feet, you don’t have many choices in the cable world for that reason—Monster says it’s soon headed for 100 feet of HDMI.) Couple that with staples, kinks and other weirdness that might happen with in-wall installation, and the fact that when you upgrade your TV, you don’t want to have to re-do your drywall, and Monster has a good point.

Lest you think I be drinkin’ Lee’s Kool-Aid, here are my caveats to Monster’s truths:

• If you are going from any source to a 720p or 1080i TV set, you should really be in the clear using a full-on crappy ass cable.

• As long as you’re not doing installing the wiring in your wall, start with the crappy cable. If it sucks and you only paid $20 for it, go back and spend more on something certified.

• In the demo, Monster even proved that good components can offset crappy cables: that PS3 and that Samsung 1080p were able to work around much of the problems, all the more reason why, in a non-custom non-in-wall installation, you should try out the lower grade stuff first.

So listen, you’ve heard it from me: there are differences in cable, but there are also differences in technical requirements. We don’t all need $120 cables for our components. As to the question of why Monster won’t offer a lower-priced product in recognition of these differences in technical requirements, Lee told me to “stay tuned.”

15
Jul/09
0

What’s the Matter with HDMI?

whatishdHow the designers of the HDMI standard screwed up, and what’s to be done about it.

HDMI, as we’ve pointed out elsewhere, is a format which was designed primarily to serve the interests of the content-provider industries, not to serve the interests of the consumer. The result is a mess, and in particular, the signal is quite hard to route and switch, cable assemblies are unnecessarily complicated, and distance runs are chancy. Why is this, and what did the designers of the standard do wrong? And what can we do about it?

The story begins with another badly-developed standard, DVI. A few years ago, there was a movement within the computer industry to develop a new digital video display standard to replace the traditional analog VGA/RGBHV arrangement still found on most computer video cards and monitors. Interested parties grouped together to form the Digital Display Working Group (DDWG), which developed the DVI standard.

DVI had all the earmarks of a standard designed by committee, and it remains one of the most confusing video interfaces ever. DVI could run analog signals, digital signals, or both, and it could run digital signals either in a single-link configuration (in a cable using four twisted pairs for the signal), or in a dual-link configuration (using seven). Identifying which DVI standard or standards any particular device supported was not always easy, and the DVI connector came in various flavors and was never really manufactured in any form that wasn’t well-nigh impossible to terminate.

But the worst thing about DVI was something that the computer-display professionals involved in its development really didn’t give much thought to: distance runs. Most computer displays are mounted at most a few feet away from the CPU, so it didn’t seem imperative that DVI work well over distance. This lack of concern for function at a distance, coupled with common use of twisted-pair cable (e.g., CAT 5) in computer interconnection, led to a decision that DVI would be run in twisted-pair cable.

Had the DVI standard been designed by broadcast engineers rather than computer engineers, things probably would have turned out very differently. In the broadcast world, everything from lowly composite video to High-Definition Serial Digital Video is run in coaxial cables, and for good reasons, which we’ll get to in a bit. Long-distance runs of VGA, in fact, are always handled in coaxial cable (though there may be a number of miniature coaxes in a small bundle, rather than something which obviously appears to be coax).

whatishd1DVI lacked a couple of things which the consumer audio/video industry wanted. It was implemented on a variety of HD displays and source devices, but it was confusing for the consumer because of the many variants on the standard and different connector configurations, and it didn’t carry audio signals. A consortium to develop and promote a new interface, HDMI, was formed; the idea was to come up with a standard which could be implemented more uniformly, was less confusing, and offered the option of routing audio signals along with video.

Here, again, was an opportunity to avoid problems. The difficulties of running DVI-D signals over long distances were well known, and the mistakes of the past could have been avoided by developing HDMI as a wholly new standard, independent of DVI. Instead, the HDMI group elected to modify the DVI standard, using the same encoding scheme and the same basic interface design, but adding embedded audio and designing a new plug. Instead of many DVI options, analog, digital, single and dual link, there was one “flavor” of HDMI (actually, there is also a dual-link version in the HDMI spec–but you won’t find it implemented on any currently available device). This provided the advantage of making HDMI backward-compatible with some existing DVI hardware, but it locked the interface into the electrical requirements of the DVI interface. Specifically, that means that the signals have to be run balanced, on 100 ohm impedance twisted pairs.

We’re often asked why that’s so bad. After all, CAT 5 cable can run high-speed data from point to point very reliably–why can’t one count on twisted-pair cable to do a good job with digital video signals as well? And what makes coax so great for that type of application?

First, it’s important to understand that a lot of other protocols which run over twisted-pair wire are two-way communications with error correction. A packet that doesn’t arrive on a computer network connection can be re-sent; an HDMI or DVI signal is a real-time, one-way stream of pixels that doesn’t stop, doesn’t error-check, and doesn’t repair its mistakes–it just runs and runs, regardless of what’s happening at the other end of the signal chain.

Second, HDMI runs fast–at 1080p, the rate is around 150 Megapixels/second. CAT5, by contrast, is rated at 100 megabits per second–and that’s bits, not pixels.

Third, HDMI runs parallel, not serially. There are three color signals riding on three pairs, with a clock circuit running on the fourth. These signals can’t fall out of time with one another, or with the clock, without trouble–and the faster the bitrate, the shorter the bits are, and consequently the tighter the time window becomes for each bit to be registered.

Consider, by contrast, what the broadcast world did when it needed to route digital video from