I Think We’ve Got A Lead…

January 14th, 2006 by Ben Goldacre in adverts, bad science, Hi-Fi, references, statistics, very basic science | 113 Comments »

Ben Goldacre
Saturday January 14, 2006
The Guardian

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 £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 £140. Stone Audio will sell you the “Super Mains 25 HARDLINK Polished Rhodium Plated UK 13A Supergrip Plug” for £150. And Cheshire Audio will sell you the “Experience Mains 32a – possibly the ultimate mains lead” for a modest £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 £400 cable, a £30 cable, and a £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.

· Send your bad science to bad.science@guardian.co.uk

If you like what I do, and you want me to do more, you can: buy my books Bad Science and Bad Pharma, give them to your friends, put them on your reading list, employ me to do a talk, or tweet this article to your friends. Thanks! ++++++++++++++++++++++++++++++++++++++++++

113 Responses

  1. Tom said,

    March 16, 2006 at 1:54 pm

    Will any sort of test ever be undertaken? If I was spending hundreds on a power cable I think I’d like to see some major improvements in sound quality, surely even a flawed test would reveal this.


  2. Nick P said,

    March 19, 2006 at 7:03 pm

    > If I was spending hundreds on a power cable I think I’d like to see some major
    > improvements in sound quality
    Quite agree!

    > surely even a flawed test would reveal this.

    The methodology proposed – make “with” and “without” recordings & distribute then for us to assess – is fraught with assumptions and introduces uncontrolled variables.

    Just some of the pitfalls:
    – Recordings will be made from source or pre-amplifier stage; suppose the biggest effect is at the power amplifier stage? That part of the sound reproduction chain won’t figure in the trial.
    – How will we know that the recording apparatus is capable of reproducing the difference between a $10 radio and a top-notch hi-fi? Between hi-fis of different quality? Until the whole recording process is calibrated, it’s useless.
    – On what will the recordings be played? If we’re recording from a high-quality source, will a low-quality reproducer – a computer’s sound system – be capable of reproducing any differences?
    – Will the recordings be made to the highest possible quality? Bit rate? Compression?

    If the apparatus ain’t up to it, the experiment is _worthless_. A flawed experiment, by definition, reveals nothing: if the uncertainties in the measurements are as big as they would be in this case, _all_ apparent differences disappear once the error analysis is complete (sample “A” measured 10, +/-25; sample “B” measured 15, +/-25; result? No _significant_ difference)


  3. El_Cid said,

    March 31, 2006 at 6:36 pm

    One question for the studio engineers (past & present) who have posted here:

    In an earlier post I raised the question not just of whether or not these different cables etc. changed the sounds being reproduced, but whether or not changing the sounds being is even desirable.

    Again, if the studio engineers recording the actual mix decide what it is which we will hear in the final, recorded, and purchaseable recording (CD, LP, whatever)…

    …wouldn’t we want to exactly reproduce what it was they were mixing?

    For example, if the studio engineers didn’t use such and such a power cable or speaker wire or interconnect, why would a listener to the recorded object want to do so and change the result?

    Do I really want to bring something out of the sound which the engineers didn’t want? Say, the volume of the air conditioning in the room? Etc.

    And doesn’t this obsession with the realism of the audio reproduction then lead directly to the goal of owning in your home exactly the same equipment which the studio engineers used?

    Which is to say, again: if the tweaker community’s claims of cable / speaker wire / interconnect effects are granted, aren’t these effects actually undesirable?

  4. Steve Hill said,

    April 2, 2006 at 9:34 pm

    I run a commercial recording studio. I can listen to recordings through half a dozen different sets of speakers and amplifiers ranging from “grot boxes” (to check stuff sounds passable on e.g. a cheap ghetto blaster) to the somewhat esoteric. I listen in an acoustically treated monitoring environment designed to give the best possible stereo image.

    In the recording process sound travels through a variety of bits of equipment (mixers, guitar amplifiers, compressors, equalisers, reverb units, computers etc) all of which have main supplies. Some high-end (valve) microphones also have mains leads.

    These are all “ordinary” kettle leads. If I used anything else it would not make the blindest bit of difference to the recorded sound.

    Almost everybody I know in the industry would say the same. I know of a couple of people through internet forums who would defend the Russ Andrews £30 leads, as serving a useful purpose (they do work; they are not going to add to your noise problems) and in fairness you can also buy “better” kettle leads at Maplin. But I know no-one in the industry who would go further upmarket [e.g. to “Valhalla” mains leads costing $1,750 and which claim to actually speed up the flow of electricity to your amplifier!!!]

    I would be interested in getting involved in the projected test should it ever happen.

  5. Non-Dr Tim said,

    May 19, 2006 at 7:38 pm

    Yes, true, but if you place a glass of French carbonated mineral water, precisely equidistant, between your speakers (must be French and carbonated – the English flat stuff is no good and the Italian stuff causes sub-molecular interference) then you’ll achieve the same effect as Rhodium plated power leads for a much lower outlay. You have to replace it every day ‘tho, and a slice of lemon and some ice helps ;-).

  6. tringo said,

    December 5, 2007 at 11:53 am

    I agree with the basic premise of this article, but there’s a glaring error which no-one seems to have pointed out:

    “…(the “50Hz” of the mains supply), which are necessary for your equipment to work…”

    Amplifiers and most electronic equipment (there’s bound to be an exception somwhere) uses DC (direct current), not AC (alternating current). The electricity supplied from the mains will be rectified – converted from AC to DC – in the power supply of the amp, and then, yes, smoothed by a series of capacitors. The point being your equipment does not need AC to work!
    Bad science? I think so!

  7. Daedalus said,

    January 18, 2008 at 4:14 pm

    The Wall Street Journal (of all publications) did the experiment and found a small but significant benefit. See the “Portals” Column by Lee Gomes Page B1 16 Jan 2008. The following is an abridged version:

    “I set up a room with two sound systems, identical except for one component. Everything except the speakers was hidden behind screens. With the same music playing on both, participants used a remote control to switch between the two, and then tell me which sounded better.

    Using two identical CD players, I tested a $2,000, eight-foot pair of Sigma Retro Gold cables from Monster Cable, which are as thick as your thumb, against 14-gauge, hardware-store speaker cable. … of the 39 people who took this test, 61% said they preferred the expensive cable.

    That may not be much of a margin for two products with such drastically different prices, but I was struck by how the best-informed people at the show — like John Atkinson and Michael Fremer of Stereophile Magazine — easily picked the expensive cable. Its sound was described as “richer,” “crisper” and “more coherent.” In absolute terms, though, the differences weren’t great. Mr. Atkinson guesstimated the expensive cables sounded roughly 5% better.”

  8. Hifiwigwam said,

    January 26, 2009 at 11:24 pm

    Interesting post on the monster cable test above. I am lead to believe that Monster fund a lot of tests and research into very specific areas of audio cables ..ahem. I shall probably leave it there.

    My main reason for posting is that the link at the top of the page is still sending people our way. However the rather embarrassing thread it links to has now been removed. After we all got hot under the collar and accused Ben of all sorts of nonsense in some rather shameful ad homonym attacks, a few of us calmed down enough to put our faith to the test. The test, method and results can be seen here:

    For those that can’t summon the teeth grinding will required to read it all, I shall summarise: The test tried to show that there were audible differences between three power chords of varying cost and build, and that the more expensive cable would out subjectively out perform the cheaper ones. The result was that listeners could not reliably detect the more expensive cable under blind conditions. Although most listeners did report audible differences, no useful correlation could be found from one report to another. Expectation bias would account for those reported differences quite easily.

    It is in fact thanks to this thread and to Ben posting on the WigWam that we now have an area of the forum dedicated to objective testing and as much as it upsets the die hard foo heads, we now have a bit of a reputation for “foo busting”!

    Personally, I am now a confirmed foo free zone, and now reject after market cables in the same way that I always rejected homeopathic dream catchers and tie died sarongs. So, well done bad science..

    Oh BTW Ben, the book is really nicely written, I have enjoyed reading it and the part on Placebo is perfect ammunition in so much foo busting.. I have sent a copy to my homeopathy obsessed sister in law.. I doubt she’ll read it but it’s worth a try!


  9. wayscj said,

    November 23, 2009 at 12:31 am

    Laptop Battery Laptop Battery Laptop Batteries
    Laptop Batteries discount laptop battery
    discount laptop battery
    notebook battery notebook battery
    computer battery computer battery
    replacement laptop battery replacement laptop battery
    notebook batteries notebook batteries

  10. jiangjiang said,

    December 8, 2009 at 2:02 am

    ed hardy ed hardy
    ed hardy clothing ed hardy clothing
    ed hardy shop ed hardy shop
    christian audigier christian audigier
    ed hardy cheap ed hardy cheap
    ed hardy outlet ed hardy outlet
    ed hardy sale ed hardy sale
    ed hardy store ed hardy store
    ed hardy mens ed hardy mens
    ed hardy womens ed hardy womens
    ed hardy kids ed hardy kids ed hardy kids

  11. linskoflondon said,

    March 5, 2010 at 9:22 am

    WOW Gold
    |Cheap WOW Gold

  12. shengrui3 said,

    June 24, 2010 at 2:03 am

    Thank your for your articles. I learn more from here! Thank you !

  13. Bad Science said,

    January 17, 2011 at 3:39 am

    […] […]