HDTV Forum

Is there a real difference in the various brands of cables? Is a $120 cable that much better than a $20 cable? I can see (and hear) a difference in analog cables, but is this true for digital cables too?

Hi-
My 'vote', based on (1) person's usage / esperiences..

Everything for sale currently has reference to 'Digital,
HighDefinition...' & MOST of it is straight out of the
playbook by P.T. Barnum !!!! " A sucker born every minute!"

YES, every cable MUST have quality terminations, a minimum gauge conductor ( doesn't apply to optical, of course) and gold flash has it's place.

That said,( 2 ) meter-6'- "HDMI" from MONSTER or APPLE.COM will EACH deliver perfect HDTV unless they are specifically, individually defective. Take that one back for an exchange, etc.. Otherwise, pass on these Outrageously-Priced $200
and higher Specials!! eli whitney

All interference or "noise" affects an analog signal. However, this is not true of digital. With digital, the interference has to be high enough to prevent the passage of the signal. Unless a cable is broken, it will pass a flawless digital signal--even if it costs $5. This is also true of home optical connections. I agree 100% with the P.T. Barnum reference!

For short cables it doesn't matter much. With longer cables you need better shielding to prevent interference. Beyond that there isn't any improvement to be had with exotic materials or construction techniques.

With digital signals, length is not a question of additional interference (which affects analog signals) but a question of maintaining threshholds between the "on" and "off" digital states and of signal strength. HDMI in particular is affected by cable length and long lengths sometimes require signal amplification for handshaking, etc. to work properly. I am using a 62 foot "amplified" HDMI cable to my front projector that works perfectly.

I also concur that the P.T. Barnum refercence is spot on.

I agree that signal strength is probably a bigger issue but anytime you have long copper cables I think interference is a potential issue even though digital can recover from a certain amount of interference automatically.

No, all signals now are DSP (digital signal processing) therefore it's all or nothing. The only time it would really make a difference is when you're using longer than usual cables but even then the "brand" of cable shouldn't matter.

For example, I can use my hold RCA cable for my coax out on my DVD player or (DTV display) into my compatible receiver and receive the same 5.1 Digital audio as if I purchased a $50 cable that claims to have "Monster" capabilities.

Just think of your cell phone. Now at days many of them are GSM. You either have a good two way signal or you simply cut out, there's no middle.

Right, but too much interference will cause the signal to drop - but as you say that's typically only a problem on longer cables.

I bought either a 3' or a 6' HDMI cable from a recommended source and I can't say enough about the price and shipping efficiency and charges. The cable was about $6 and shipping was very reasonaable; I had it in slightly less than a week. I was recommended to mycablemar.com by someone on this forum and ama extremely happy compared to the PT Barnum prices.

I agree with the idea that a ten dollar, three meter cable, bought from a reputable dealer, is all you need. The beauty of digital signals is that you don't have to sit around wondering if your picture is somehow sub-par because you didn't buy the "better" cable. If your picture is stable, your cable is working.
The story with long cables, say greater than ten meters, is somewhat more complicated than indicated in the prior posts here. For long cables, cable design is critical. The HDMI signals are carried on several twisted pair wires. The two wires in each twisted pair carry the same signals, but with opposite polarities. The receiving electronics look at the voltage difference between the two wires to determine whether that piulse pair represents a zero or a one. This technique, commion to many other digital busses, is relatively immune to interference. The reason is that the interfering signal tends to add to both wires, in the same way. The receiving electronics disregards the interference because it is looking at the differece in voltage between the two wires, which both have been purturbed by the same amount, and in the same voltage direction. In reality, the interference won't add or subtract from both wires by exactly the same amount. So, over a long cable length, that differebnce may cause the receiving device to read the signal incorrectly. So, for long cables, shielding and impedance matching becomes important. If the desired signals are prevented from dropping too low, due to cable losses, the effect of this interference error can be minimized. Amplifying the signals before they drop too low is required.
There is a second effect that can cause errors in long cables. In the twisted pair, each wire is carryiing a fast pulse with opposite polarity. The speeds with which the pulses travel down the two wires from input to output are a function of electrical length of the individual wires. Electrical length is a combination of the actual wire length and the effect of inductive and capacitive coupling to it's surroundings. If the electrical lengths of the two wires in a twisted pair are different, then the two pulses carried by the two wires in the twisted pair will arrive at the receiving device at slightly different times. Therefore, the receiving device may not be able to correctly measure the voltage differece between the two wires, because the two pulses don't line-up correctly. The only way this problem can be prevented is by good design and quality manufacturing techniques. So, for long cables, buying from a source that actually tests their cables is critical.