Saturday January 14, 2006
Ok, hold on to your girlfriends, because this time we get seriously geeky. Last week we were talking about hi-fi company Russ Andrews, and their Â£30 power cable, which they reckon will improve the sound of your stereo. It’s not a speaker cable, or a even a posh cable connecting your CD player to your amp. It’s a power cable, from the wall socket to your hi-fi, a bit like a kettle lead.
I expressed doubts that this would do much good. It turned out it was just the tip of the power lead iceberg. Russ Andrews have another one for Â£140. Stone Audio will sell you the “Super Mains 25 HARDLINK Polished Rhodium Plated UK 13A Supergrip Plug” for Â£150. And Cheshire Audio will sell you the “Experience Mains 32a – possibly the ultimate mains lead” for a modest Â£470, although they don’t make any specific claims about sound quality.
Now, interestingly, since last week, Russ Andrews have written in to explain how they believe their cable will filter out radio interference in the power supply, and so improve the sound of your stereo. Pay attention. They say their power cable has “a woven profile which takes advantage of the known effect of capacitive RFI cancellation of crossing wires, with the longer the cable and the more crossings in the weave, the more cancellation”.
Basically, what they are saying is, that the twists in the cable mean it acts like an electronic component called a capacitor. There is a geeky explanation for why this might filter out radio frequencies (to keep the pedants happy) and a simpler one (for those of you with a sex life).
The geeks’ explanation, which I honestly suggest you ignore, is this: a capacitor will allow higher frequencies, like radio frequencies, to pass through it, and go to ground. That is, it will “short them out”, take them off out of the cable, but will not affect the lower frequencies. I’d love to explain more about the fascinating subject of “capacitative reactance” to you on the news pages of a national newspaper, but I’d get the sack, and they’d probably give my job to the person who writes Ask Emma.
So here is a simpler explanation. You could think of this system as being a bit like suspension on a car: small, quick, one-inch-tall bumps will get filtered out by the springs in your suspension; but when you drive over a 200-yard-long one-inch-tall platform, your car does lift up into the air by an inch, while you’re driving over it.
The radio frequency interference can be thought of as very quick small bumps in the electricity supply, maybe a million little bumps every second, which a capacitor could filter out; but the mains supply also has big wide humps going up and down very slowly, only 50 times every second (the “50Hz” of the mains supply), which are necessary for your equipment to work, but which the capacitor won’t be able to affect, because they’re going up and down too slowly.
That’s the theory. But there are two problems with this. First, the people selling these cables are hardly the first people to notice that radio frequency interference in the mains power might mess up the sound of your hi-fi, so the power supply in your equipment will be chock full of all kinds of deliberate tricks to filter it out, and they are a lot better than a Boy Scout improvised capacitor made from a twisted bit of wire.
Then there is the most important issue. Forget the theory, however damning: can anyone hear a difference? I don’t mean, can you “hear” it when you know how much it costs, and you know you’re using it, and you know what you ought to hear.
No. What I want to know is: can you tell the difference between a Â£400 cable, a Â£30 cable, and a Â£1.50 cable, if you don’t know which one is being used at the time? That is a double blind trial. That is what I plan to do, and I need hi-fi reviewers and pedlars: so far I have two promises, but I need more. It will take an afternoon, but it will be worth it, and I’ll make sure it gets published somewhere. And if nobody volunteers I shall start choosing subjects myself. My email address is below.
Â· Send your bad science to firstname.lastname@example.org