It happens at the best electronics stores. You're already dropping $700, $1,000, or more on the latest LCD or plasma TV, and perhaps another chunk of change on a Blu-ray player or gaming console to go with it. Then the sales rep reminds you: You need cables to connect all your high-definition devices.

The choices are bewildering - as, at most stores, are the prices. Name-brand HDMI cables, such as Monster, often sell for $100 or more. And even when a cheaper version is available, such as Best Buy's Dynex house brand, many salespeople will steer you to Monster - or maybe to Rocketfish, another Best Buy house brand that's just slightly less pricey.

Is a costly cable really worth the money? Or is it simply the latest version of the high-markup add-on, like the extended warranty some stores also pitch?

In a recent test of brand-name vs. no-name HDMI cable, PC magazine reached the same conclusion others had: Don't waste your money.

PC magazine's Will Greenwald put it succinctly: For the vast majority of home-theater setups, the pitch that you need "special" or "superior" cables is "utter rubbish."

"It's like saying you can get better-looking YouTube videos on your laptop by buying more expensive Ethernet cables," Greenwald wrote. "From a technical standpoint, it simply doesn't make sense."

The good news is that you can anticipate your HDMI cable needs before you buy your new high-def equipment, and shop online for cheaper cables beforehand. The huge markups charged by brand-name cable-makers and retailers have left plenty of head room for Internet entrepreneurs who sell quality cable for a fraction of the price charged by Monster and its spawn, and less even than discount stores such as Target and Wal-Mart.

Why buy high-priced cable? Noel Lee, "head monster" at California's Monster Cable Products, says the answer is that its top-quality cables protect consumers against technological advances.

For about $100, he says, Monster offers a six-foot cable rated at 15.8 gigabits per second, about 50 percent more than the 10.2-gigabit minimum required to qualify as "high-speed HDMI cable" according to HDMI.org, the consortium that manages HDMI standards and licenses a logo to certify products that meet its requirements.

"The quality of sources and the quality of TV displays go up every year," Lee says. "We offer the higher-end cables so people don't have to worry."

For a contrasting viewpoint, I spoke with Kurt Denke, the founder of Seattle-based BlueJeansCable.com, which sells its own top-quality six-foot high-speed HDMI for about $22 and a six-footer fine for most uses for less than $4.

"The biggest fallacy is that price equals quality," says Denke, a Penn law graduate, who in the 1980s founded Center City's venerable Home Sweet Homebrew with his wife, Pam Moore.

After selling the store and moving back to his hometown, Denke again found himself dissatisfied with life as a lawyer, and saw opportunity in the making and online marketing of audiovisual and computer cables. HDMI now accounts for about 40 percent of his business, so I asked him for help in demystifying the cable market.

Denke says HDMI, like most cable, is largely "just wire and plastic." It carries 19 conductors - strands of wire - that are soldered to a connector plug at each end. "The backside of the connector - the part you never see - is just a little chunk of a printed-circuit board," he says.

As a digital data carrier, HDMI isn't subject to the same kinds of problems that trouble analog transmissions. It either works or it doesn't.

How can you tell? If an HDMI cable is working properly, you get a clean picture. If there is data loss, you'll see obvious problems, such as stray horizontal lines, or what viewers sometimes call "sparkles" - a little like "snow" on an analog TV. Both are evidence that your digital data stream has been degraded.

Denke says that misunderstandings are common, and that he believes they're fueled by the desire to sell costlier cable.

"HDMI-cable failure is never subtle," Denke says. "You will never be able to find two HDMI cables where one renders better shadow detail, or delivers sharper color transitions, than another." The reason is simple: Those aspects of the display are governed by the digital data decoded by your TV.

Also causing confusion are the evolving standards set by HDMI.org as it adjusts to new features offered by device-makers, such as the proliferation of standards for "surround sound" or color depth.

If your Blu-ray player uses features new in version 1.4, you want your TV to meet the same standard. But aside from defining a separate high-speed standard, and the recent addition of special versions that integrate an Ethernet cable into HDMI, "nothing material has changed in the cable" since HDMI was invented, Denke says.

So why buy his $22 cable rather than his $4 cable? Denke says his best cables use "bonded-pair" wires rather than twisted wires, and work better over long distances - the enemy of error-free data carriage. If a customer is "daisy-chaining" cables, say, for an in-wall installation, the higher-quality cable makes sense, he says.

"You start seeing problems with lengths above 25 feet," Denke says.

For short lengths, his advice is simple: Spend as little as possible, and you'll get cable that works as well as the highest-priced alternatives.

That way, you can keep the price monster safely at bay.

Contact columnist Jeff Gelles
at 215-854-2776 or jgelles@phillynews.com.