http://lamkins-guitar.com/music/article/magic-cables
David Lamkins picked up his first guitar a long time ago. As best he can recall the year was 1967: the year of the Summer of Love. Four decades later David has conjured up an amalgam of folk, rock and jazz solo guitar music for the occasional intimate Portland audience.
location: Portland, OR USA

Facets: human nature, marketing hype, cables, physics, @musings info
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On magic cables

So, you've just bought a special piece of wire. It looks just like the wire you used to buy at the hardware store, but it costs twenty times as much and comes in a handsomely-printed box covered with lofty claims. You consign your old wire to the the trash, hook up the new wire, re-read the packaging so you'll know what you're supposed to hear, and fire up the old system. And it sounds...

Different? Did you ever notice that particular bass note sounding like that? Maybe not. After all, the box said it should sound different. Of course, you probably never listened before with this particular set of expectations. And that new wire really cost a lot of money, so it must be good, right?

Sure. Either that, or you're kidding yourself. Your auditory memory simply isn't that good for the level of detail you think you're noticing. Which is convenient, because if your memory was that good it'd be really hard to kid yourself about the dramatic change you think you're hearing. Marketing people know this. Do you really think there are millions or tens of million of people with extraordinarily sensitive hearing? Or is it more likely that there are a lot of people too embarassed to admit they've been suckered by a sales pitch?

But of course, we're very sophisticated, well-educated people. We'd know the difference between reality and wishful thinking, right? History's not on your side. We take for granted simple observable truths -- like the basic concepts of gravitation and disease vectors -- that were once unimaginably heretical to affluent, sophisticated people in earlier societies. The sad truth is that most people believe what they're told to believe and never bother to check facts, much less reason about possible logical flaws in the presentation.

So if you've really gotta have that hundred-dollar guitar cord with oxgen-free domain-aligned copper and directional connections, go for it. For that kind of money, you'll probably find some difference that you can hear. Or you could go spend ten or twenty dollars for a really good cord that actually does sound better.

Guitar cords are really simple. They have to do three things well. They have to fit the jacks on your guitar and amplifier. They have to keep out electromagnetic interference. And they have to minimize the capacitive load on your guitar's pickups or on-board preamp. That's it.

The first requirement is satisfied by using a properly-machined connector. A properly-machined connector is built to tight tolerances and doesn't become wobbly with use. The connector doesn't have to be gold-plated. In fact, the gold plating is wasted unless your guitar and amp also have gold-plated contact surfaces. None do.

The second requirement is satisifed by using shielded cable. Shielding is spec'd by percentage of coverage: how much of the inner conductor is not visible through the sheilding. A coverage figure of around seventy percent is fine. Don't buy the nonsense that ninety-nine percent or higher coverage is needed. Sheilding at that level is going to be negated by your guitar and your amp, neither of which are that well sheilded. And the higher-coverage shields are only truly effective at frequencies well beyond the range of audibility.

Your guitar's pickups have a high output impedance. When you plug a cable into your guitar, the capacitance of the cable forms a frequency-dependent voltage divider with the pickups. The net result is that high frequencies -- the frequencies that give your guitar its "shimmer" -- experience a certain amount of attenuation. The longer the cable, and the more capacitance per unit length, the greater the attenuation. High-capacitance cables make your guitar sound "dull".

For a given length of cable, three things determine its capacitance: the dielectric properties of the inner insulator (i.e. how much electrical charge they retain), the surface area of the coaxial conductors, and the distance between the conductors (i.e. the thickness of the inner insulator). PVC insulators are cheap and flexible, but have a high dielectric constant and therefore a high capacitance. A few manufacturers use other material to obtain lower capacitance at a nominal increase in cost. Ironically, total-coverage shielding works against low capacitance because of the increased surface area of the shielding conductor.

There's about a three- or four-to-one range in the capacitance of commonly available guitar cables. If you don't think that much variation is important, try this experiment: Buy two of your favorite-brand cables, one in a twenty foot length and the other in a six foot length. Set up your guitar and amp with the guitar plugged in through the twenty foot cable. Tune carefully. Play and listen to the high harmonics and the interactions between notes in a chord. Now, without changing anything else, swap in the six foot chord. You'll probably be able to hear the difference. If you like what you hear (and you may not - you may prefer the darker sound of the longer cable) then you may want to look for a lower capacitance cable so you don't have to stand so close to your amp.

July 13 2003 07:51:15 GMT