Wednesday, March 14, 2007

ANALOG CABLES vs DIGITAL CABLES

Manufacturers and retailers have been ripping off consumers for some time now when it comes to cable quality. I would like to set the record straight:

ANALOG CABLES: Analog signals are provided by converting the information, from the DVD player for example, into a fluctuating signal or current, sent down a cable, and the information is put back together on the other side. This process alone causes for the loss of some information which on a tv, reduces quality. The quality of the cable, the shielding (insulation to prevent the signal from escaping from the cable), and the quality of the connectors determine how well the signal will transfer from device to device. The following are examples of analog cables rated in order of quality. We'll go from worse to best:

RCA/ PHONO/COMPOSITE: VCR's made this cable popular in the 80's. Phono was a older term used to relate to the red and white cables that is used for audio. Composite, is the yellow cable that is used for video which is also known as an RGB (red, green, blue: primary colors for video) signal. This type of cable provided a noisy signal due to the fact that the signal is converted a couple times before finally being output to the tv. It is easily intereferred by other signals around it.

SCART: Provides a slightly superior video signal than RCA and is used primarily in the European market. It carries both audio and video at the same time, and very interestingly can output via an S-VIDEO or RCA adapter, but not at the same time. Video quality cannot exceed RGB, and sound is also limited to 2-channels (stereo) which means it cannot transfer surround sound.


S-VIDEO: or Separate Video only provides a video signal. It carries resolutions at 480 or 576 using the interlaced method. It is still widely used today and is classed as a "standard defintion" cable as it meets the resolution for SD (480i).


COMPONENT: Unlike S-Video, a component cable separates the three "additive primary colors"(the primary colors that TV signals use, and not the primary colors red, blue and yellow) into separate "components," which is where the name comes from. By separating the colors, each cable can maintain signal clarity and avoid interferance or noise from the other cables. This is the highest quality analog cable and supports resolutions of 480i, 480p, 576i, 576p, 720p, 1080i, and 1080p.

DIGITAL CABLES: This digital connector works differently from the analog cable, because essentially, it sends the signal "digitally." This means it send "1's" and "0's" down the cable instead of a fluctuating signal. As a result there is no real loss of signal, you either get it, or you don't. These bits of information are assembled back together after they pass down the cable.
One of the primary advantage of the digital cables over the analog, is that they offer more than 24-bit color, which it the max for analog connections. This means a difference of 17 million colors with an component analog connector, and 1Billion- 2800Trillion colors with a HDMI cable from a HDMI 1.3 device!


DVI: When HDTV's first came out, they had DVI (Digital Video Interface) connectors, which was the High Definition connection standard at the time. DVI is still very much present as a means to interface between PC's, monitors and select HDTV's. It is partially compatible with HDMI (High-Definition Multimedia Interface) which it the new HD standard connector. It is important to note that dvi ONLY transfers hd VIDEO between devices.


HDMI: No more than a year later, HDMI replaced DVI due to major support from all the top players in the industry. HDMI is now the new standard for the transfer of High Definition audio and video. It is a single USB like connector that is increasingly being implemented in HDTV's, some upscaling dvd players, home theatre receivers and Blu-ray and HD-DVD drives. Unlike DVI, HDMI allows both HD audio AND video to pass through using just the one connector. It also includes High-Bandwidth Digital Content Protection (HDCP) which is the new, digital form of copyright protection to prevent copying HD content. HDCP adds a new layer of compatibility issues, so make sure your tv and devices are all HDCP compliant. HDMI version 1.3 is on the horizon and it offers the higher end specifications listed in the chart above as well as many other features for improved picture performance.

Now that the descriptions are out of the way, we can get back to the main issue. To put it bluntly, when it comes to analog cables, the quality of the cable DOES matter.
You need a well built, well insulated cable as signal "information" can be lost through poor insulation, distance or cheaply made connectors. This doesn't mean go out and buy a $100 component cable. There are several online retailers such as our Amazon store that sell high end component cables at around $35 for a 25ft. Markup at local retailers is HIGH. This is where they make a lot of money. Don't buy into the marketing. "Monster cables" have done a great job of conning consumers into thinking they were getting what they were paying for.

With digital cables, quality of the cable is much less of an importance than analog. Yes, you need a good connector, good shielding etc, but that's so the thing doesn't break and so that the signal can get from one side to the other without interruption. But once the signal makes it to the other side, picture quality is going to be as good as the source it came from. No better or worse. The only time when extra sheilding comes into play is over long distance. We have what you call "tenuation" which is loss of signal over distance. To be safe and to not get too technical, if you're going over 25ft, I would increase the AWG (American Wire Guage), in other words the guage or thickness of the cable. Maybe increase a little more if you're going over 50ft. But again, because it's a digital signal, the difference may not be noticeable.

If you're not convinced, With the great return policies some stores have, you can take advantage and buy yourself a $200 Monster HDMI cable then go here and buy the same spec cable for a 1/3 or the price and do a comparison yourself! Whichever way you go, you can always return the other! Guaranteed, you'll take the Monster cable back!

1 Comment:

Paul said...

It looks like my installer used an old three way analog and put colored electrical tape around the tip to designate the red, blue and yellow... If I use a component cable vs. a this three way simple red, blue, yellow cable will there be a difference in quality of my blue ray image on the tv?