Voodoo HiFi Experimental Design Masterclass

February 4th, 2006 by Ben Goldacre in bad science | 341 Comments »

Ben Goldacre
Saturday February 4, 2006
The Guardian

Folks are the same the world over. Now, as far as I know, I’m the only person in this room who’s had violent threats – in writing – from angry alternative therapists. If that’s not true, of course, I’d love to hear your story, but either way, I feel pretty well placed to assess the emotional temperature behind the stranger end of popular belief.

So let’s talk about the high end hi-fi industry. I wrote about their very expensive power cables last month, ranging from £30 to a whopping £1,800, for what is, after all, a kettle lead to connect your stereo to the three pin power socket in the wall. The various manufacturers claim that their cables will filter out radio frequency interference in the power cable, and that this will improve the sound. I doubted this, and the outpouring of bile that was subsequently vomited in my direction (references on badscience.net) surprised and delighted even me. But what was most interesting, to students of this stuff is that the angry outbursts came primarily from the natural constituency of Bad Science readers. Several were deeply wounded. Homeopathy was one thing, they said, but this time, I had clearly got it wrong.

And that was when I started to notice the frightening similarities between the thought processes of the alternative therapy fans and the hi-fi freaks. Both make an appeal to personal experience, as the highest and most valid form of measurement; both use mystifying, scientific-sounding terminology in their publicity material; and both use the appeal to authority.

But the most striking parallel is the widespread notion in the hi-fi community that blinded trials – where you ask listeners to identify a cable without knowing if it’s cheap or expensive – are somehow intrinsically flawed. This is exactly the card that the alternative therapy community have been playing, almost since blinded trials were invented.

I give you the editor of Stereophile, a respected hi-fi magazine of 33 years standing. He’s talking about blinded tests on amplifiers: “It seems,” he says, “that with such blind listening tests, all perceived subjective differences … fall away … when you have taken part in a number of these blind tests and experienced how two amplifiers you know from personal experience to sound extremely different can still fail to be identified under blind conditions …” Now I’m getting worried. Here comes the money shot. “… then perhaps an alternative hypothesis is called for: that the very procedure of a blind listening test can conceal small but real subjective differences.” Ouch. “Having taken part in quite a number of such blind tests, I have become convinced of the truth in this hypothesis.” What voodoo is this? If there is a difference to be heard, then you will hear it.

The manufacturer of my expensive power cable has assured me that it will have an impact on the sound of an expensive CD player, or a cheap one, and that it will affect optical outputs as much as normal phono outputs. So I propose, as a pilot study, to place, on badscience.net, two files, clearly labelled, one recorded from the CD player powered by the expensive cable, one powered with a normal kettle lead. There will also be a third file, and you can vote on whether it is the expensive cable, or the cheap one. This is called an A/B/X trial.

You can do what you like to identify them: burn it to a CD, listen with headphones, examine the raw data, whatever. But the catch is this: it’s a palaver, and I’m not going to bother, if the hi-fi buffs are just going to bleat about how unfair the test is. So this is your chance to participate in the design of an experiment. Post your thoughts on badscience.net. I want everybody to be happy.

· Please send your bad science to bad.science@guardian.co.uk

Please post your thougts about how best to design the experiment below. Audiophiles, I know you will find this difficult, but I’m not sure we want to have another long discussion about whether this power cable makes a difference, you can have that out here for example… it might be good to keep this thread for discussing how to test whether there is a difference.

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! ++++++++++++++++++++++++++++++++++++++++++

341 Responses

  1. mike gover said,

    February 10, 2006 at 7:27 pm

    Has anyone ever heard a CD of any kind of acoustic music or singing, that sounded indistinguishable from a live performance? The more I listen to my hifi the more I want to buy tickets for the real thing. You can run a test to see if file A sounds different from file B, and this seems a valid test of the manufacturer’s claim.

    But anyone unaccustomed to listening to live unamplified music is not qualified to say whether A is better than B. FWIW my ‘golden rule’ on hifi is that over a long period you should not spend more on equipment and CDs than you spend on tickets for concerts.

  2. Andy said,

    February 10, 2006 at 8:13 pm


    Going by your comments here (295) I would take a guess that you have never designed anything requiring a high accuracy clock.
    Yes, generating a clock that if fairly good is trivial. A 32.768kHz standard quartz crystal, an inverter, a couple of caps and maybe a resistor or two. Feed the output into a 16 bit counter and you have a nice accurate 1 second clock.
    It’s accurate enough that the clock only wrong by around one hundred parts per million (PPM). Plus temperature effects. Plus ageing effects. Plus vibration effects (crystals are an electro-mechanical device after all). In other words fine for a watch but far from perfect.
    Have you seen the size of the crystals and support circuit on a high end GPS (I’m talking a >$10k type of system)? They are big and expensive and the error on the clock must still be calculated and removed from the calculations if you want to get any sort of accuracy.

    Generating a truly accurate clock is not a trivial undertaking.

    Also a clock recovered from the data will normally pass through some form of PLL. PLL’s jitter.

    Audiophiles here have claimed to be able to hear a difference in clock jitter in the range of picoseconds. With the data rates we are talking about that is an error of 1.5 PPM. Fortunately jitter is normally far less that the total error of the clock. Still creating a clock with that sort of accuracy and lack of noise while possible is sufficiently expensive and complex that few audio manufacturers will go to the trouble. It’s certainly not something you run off in a couple of minutes.

    OK, on to the second point. Yes a fifo would remove jitter on the input. The output will be as accurate as the clock you can generate locally.
    You seem to think that a digital system is somehow magic and immune to analogue effects. That’s just not true.
    Say we have out bit clock running at around 1.5MHz. That gives us a 666ns clock period. Even if we assume the part creating the clock was perfect the line connecting the clock to the PCB is not. It has capacitance to ground, resistance and inductance. The connection from the PCB to the silicon of the fifo also has all of these. So assuming reasonable quality parts the signal on the silicon of the fifo is going to take anything from 1 to 10 ns to transition from one state to the other.
    Within that window, somewhere near the middle, we will pass through the region where the fifo decides that the input has changed. We’ll assume that internally it is all a perfect digital system.
    OK, let’s make some basic assumptions, they aren’t perfect but they give us a rough feel for the numbers…
    Assume a 1 ns rise time from 0V to 3.3V. Assume a switching threshold at 1.5V.
    The fifo will decide that the clock has changed 455ps after the clock line starts to rise from 0 to 1. So far so good.
    But no power supply is perfect, the voltage and ground will move a bit due to noise. Let’s say that the only noise in the system is from the connecting cable from the CD player. We will get noise at the edges of the recovered incoming data clock as other logic switches clocking things into our fifo. Assuming the clocks aren’t perfectly synced this will by chance line up with our output clock edge some of the time. Secondly if we use copper interconnect then there will be noise coming in on that cable connected directly to our ground plane. All this noise will have the effect of adding or removing a small voltage from our incoming clock signal, technically it’s changing the reference voltages rather than the signal itself but it’s easier to follow if you view it as affecting the signal. Let’s say that this noise it adds up to 0.01V. This means that our clock edge could be detected anywhere between 452 and 458ps after the start of the signal.
    Even assuming perfect digital function of our clock source and of the internals of our fifo we have 6ps of jitter on the output of the fifo due to some fairly miniscule noise in the system.

    OK, this is far more detail than the situation warranted but I wanted to point out that the argument “It’s digital, it is all perfect” just doesn’t work when dealing with people who think they can hear timing changes of stupidly small amounts.

  3. Drew Stephenson said,

    February 10, 2006 at 8:18 pm

    Ok Briantist & Andy
    Same question!
    Straight yes/no answer, is the test valid?

  4. Andy said,

    February 10, 2006 at 10:20 pm

    You want to limit me to just a yes or no? Where’s the fun in that?
    In my opinion yes.
    From an objective scientific point of view I would have say no.

    There are factors which are uncontrolled and/or untested, in my opinion they are sufficently small that they should not have any impact however this has not been proven and so constitutes an invalid assumption or at least a qualification on the final results.

    For even longer yes/no see my comments here(289/290).

  5. Ben Goldacre said,

    February 11, 2006 at 1:38 am

    Ok kids, good to get some issues ironed out, but we’d better get cracking on this now. Just a few practical things to be sorted:

    1. i’m going to build a webpage with links to the files and email links to vote with. if anybody thinks they ought to program a more complicated voting system then do speak now.

    2. for music, we’ve got: some stuff from the label NAIM coming on cd (i think); probably some asian electronic stuff; and some contemporary classical. if anyone can put something big glamorous and commercial in my hand with proof that i can use it without being sued then do so quickly, it’ll be much better.

    3. has anybody got a cd player which takes a kettle lead somewhere in central-ish london that i can borrow for a day?

  6. Briantist said,

    February 11, 2006 at 10:56 am


    I worked on GPS when it was still classified project back in the 1980s, so yes, I do know about high-end clocks.

    I’ve helped design and install digital and analogue TV and radio studios and used monitoring equipment over the whole digital TV network (for BBC, ITV companies, Sky, CNN, you get the idea) so yes, I do understand about the timing issues. And yes, I have had scopes out and looked at waveforms and measured all these things.

    And I’ve seen all sorts of audiovisual installations and seen many people’s reaction to them. I’ve listened to the opinion of many, many technical people in the business

    And I still listen to newly pressed records on a regular basis too.

    My illustration about building a simple quartz-based clock was that it costs only a few pennies, and you don’t even need a soldering iron. The point is that a £30 Freeview box is dealing with clock signals at bitrates that are way above that required for audio, so even a cheap bit of audio kit will be good enough, even for “Audiophiles here have claimed to be able to hear a difference in clock jitter in the range of picoseconds. ”

    This phrase makes as much sense as “Audiophiles here have claimed to be able to hear extra data bits not present in the original recording.”

    Is the test valid? Yes, in as much as any single experiment will prove anything.

    (When it does, it’s called democracy)

  7. Chris L said,

    February 11, 2006 at 8:16 pm

    Just for my own peace of mind, and possibly for the wider edification of Bad Science readers, I’ve done the experiment I outlined in posts 162 and 171 earlier this week. The results are available at www.oview.co.uk/badscience, but to summarise, ripping a CD multiple times results in exactly bit-for-bit identical files, regardless of power source or (within reason) disc surface contamination.

  8. steve mosby said,

    February 11, 2006 at 9:20 pm

    Re (307). So would there be any point in doing an extensive, elaborate listening test on those files? Is it possible they could sound different in any way that could be meaningful with regard to the effect of the original power lead?

  9. Chris L said,

    February 11, 2006 at 9:34 pm


    No, there wouldn’t.

    That was the question I asked, and suggested the likely answer to, in post 162. Clearly, there isn’t any point doing comparative listening tests on identical files – any differences listeners might hear will be entirely down to the quality of their own equipment, changes in their head position or attentiveness, or any number of other things, but cannot be due to differences in the files, because there aren’t any differences. Listening to one file and then an identical one is exactly equivalent to listening to the same file twice.

    I’m not sure if Ben’s experiment will deal with this. I strongly suspect that all three of Ben’s A/B/X files will be similarly identical. Adding a random period of silence to the beginning and/or end of each file would prevent them from showing up as equal using “comp”, but it would still be trivial to show that the non-silent bits are identical. The only other possibility would be to perform some subtle transformation on one of the files such as adding 1 to the value of every sample, but this would completely obscure the results of the experiment.

    As I’ve said somewhere higher up this thread, if the recorded files come out identical, that’s the end of the experiment – no need for a listening test.

  10. steve mosby said,

    February 11, 2006 at 11:40 pm

    Chris – I agree, and have done all along. I reckon that’s as far as the experiment needs to go. If the files are identical, the lead’s clearly had no effect. If there are differences, then further experiments could determine whether the lead caused them. Either way, I’m not sure what a listening test could really achieve.

  11. John Ruch said,

    February 12, 2006 at 6:15 am

    ‘Ben’s already stated what the manufacturer’s claims are in the first article:
    “Replacing the mains cable to any of your hi-fi or home cinema components means they perform better, giving you less distortion, clearer pictures, and more musicality, so that you enjoy your music and movies even more!”

    “The key to the success of the Russ Andrews mains cables is the unique Kimber cable weave. The woven mains cable has been proven to dramatically reduce sound-degrading radio frequency interference on the mains supply and to reject further pick up of RFI.” ‘

    This is all still generic and untestable. Nothing is quantified. “Better,” “less,” “clearer,” “more,” “dramatically reduce” and “reject further” are the adjectives/verbs. If quantifying them is left up to the testers, not those being tested–what, exactly, can possibly be proved?!

    To be completely plain: Better than what, less than what, clearer than what, more than what, dramatically reduce by how much exactly and reject further from what point?

    If the manufacturer will not say, then we will quibble about it ourselves endlessly–which is how the manufacturer has already won in the first place. Forcing the testers to actually invent the details of the claim is a classic looney trick, and this whole discussion looks like we’re falling for it. Lengthy discussions of technological standards and hi-fi inner workings do not, by themselves, constitute sound experimental design.

    This idea of just putting “data” online and letting people vote is meaningless subjectivity. It’s feeding what it’s supposedly debunking. There will be no way to tell what the results signify because you don’t know what you’re looking for (unless it’s something you quantified on your own). Most of these posts have been about inventing things to look for, or even (shudder) listen for. *The person who made the cables* must tell us that, in a quantified, testable way.

    You will have a test, but not a scientific test. The experiment does have the potential (though not at all guaranteed) to indicate whether the cables are doing something or not doing anything, but as currently constituted it will prove nothing and just generate still more arcane quibbling–including among skeptics, just you wait and see.

    At the very, very least–why in the heck are you using something as complex and taste-based as musical recordings, rather than a consistent single note that would be easy to observe and neutral in content?

  12. Rowan said,

    February 12, 2006 at 11:41 am

    Somewhat relevant to the current discussion: Freesound is a source of Creative Commons licensed samples, especially intended for use by researchers.

  13. Graham said,

    February 14, 2006 at 10:03 am

    I agree with Mike at 301. Are the gold plated cables better than the thin bits of wire held into the socket with matchsticks in the sense that they are more like a live performance? All the experiments can show is whether or not there is a difference in sound quality, not whether that sound is “better” unless you have some agreed “criteria of quality” which the listeners score. Listening to HiFi is a self-contained activity, with an ambiguous relationship to live music. And even the quality of live performance is affected by the acoustics of the hall and where you are sitting.

    Maybe HiFi is more like LitCrit than Physics.

  14. Steve Phelps said,

    February 14, 2006 at 12:42 pm

    Chris L:

    Surely it would be interesting to test the effect that the lead has on the CD-player’s DAC. If you ommit this from the test by ripping directly from CD, then a reasonable objection to the experiment would be that you have only tested a small subset of the electronic components that go into the sound-production and that a power-lead might (ok- barely) conceivable have an effect on.

    >any differences listeners might hear will be entirely down to the quality of their own >equipment, changes in their head position or attentiveness, or any number of other >things

    This is easily dealt with by random sampling. However, this is impossible to do with anonymous online voting. An online voting experiment will be seriously flawed because you would have no control over the population of listeners, their equipment, etc.. and moreover you would not even have statistics on these variables. It would be a “bad science” experiment.

    The experiment should be conducted in controlled conditions. If you want to test the hypothesis that audiophiles can tell the difference as opposed to the general public then you need to control the sample of listeners and conduct an objective calibarion test of their hearing prior to the experiment. If you want to control for factors like the fact that the lead might have varying effect on different equipment then you need to repeat the experiment with different samples of equipment. Just because the manufacterer says it will _work_ with _any_ hifi equipment does not mean that we can be any less dilligent here either- as we would not then be taking into account that just because the lead _works_ we could still get different magnitude of effect with different equipment some which will be a lot harder to detect than others. This was a serious flaw in the wine-tasting experiment reported on in one of Ben’s earlier columns- they didn’t control for varying effect with different subjects — the wine was a subject of the experiment just as much as the taster. In this case the hifi equipment and listening environment are variables that need to be controlled- and if they can’t be explicitly or meaninfully controllled then we need to introduce random sampling across different pieces of kit and different listening environments to ensure we have meaninful results.

  15. Chris L said,

    February 14, 2006 at 1:08 pm

    Steve Phelps (#314),

    I can only encourage you to re-read the original article and all the above posts – especially the one from Ben which begins “holy fucking fuck…” etc. This whole experiment was specifically proposed to test the manufacturer’s claim that their special cable would have an effect on the digital outputs of a CD player. By making this claim, they expose themselves to the possibility of an objective test. In testing that specific claim, it is not only legitimate but necessary to omit the DAC from the test.

    At the high end of the hi-fi market, CD players don’t come in a single box. One buys a CD transport, which doesn’t contain a DAC and only has digital outputs, and a separate DAC, which converts the digital signal to analog. The manfacturer’s claim is a transparent ploy to convince audiophiles that, if they want the best sound out of their system, they’ll have to buy a special power lead for the CD transport, as well as every other component.

    Fortunately, this claim is immune from all the subjective problems that your post mentions. This claim can be tested entirely in the digital domain, and answered with a completely objective yes/no result – did the special lead make a difference to the digital output of the CD transport, or not?

    That’s what this entire thread is about. Other tests would indeed be interesting, but they’re not relevant to Ben’s proposed experiment, and would be, as you say, much harder to set up, control and interpret.

    If and when it is established that the special lead makes absolutely no difference to the digital outputs of a CD transport, therefore removing any possibility that it can make any difference to the analog output of a re-clocking DAC, then we can ask the manufacturer what tests they ran, and what their results were.

  16. Ben Goldacre said,

    February 14, 2006 at 1:16 pm

    i’ve basically come to a full stop on this: none of my mates i’ve asked have got cd players which take kettle leads, so i haven’t got a cd player to test it on. anyone in north/central london who wants to help out welcome.

  17. Chris L said,

    February 14, 2006 at 1:34 pm


    You don’t think Russ Andrews will let you avoid spending £1,800 that easily, do you? 🙂 From www.russandrews.com, choose “Russ Andrews Mains Leads” from the “Mains” menu and check the Q&A panel on the left. Apparently, it’s ok to chop the current crappy power lead off your CD player and wire on a female IEC socket, so that you can then plug in your magin power lead. Female IEC sockets are available from all good hi-fi stores, B&Q, Homebase, etc.

    The two or three inches of crappy power lead that are left won’t affect the sound quality because…. errmmm… hang on, let me get back to you on that one…

    ..oh yeah. Quantum mechanics. That’s it.

  18. Steve Phelps said,

    February 14, 2006 at 4:02 pm

    “This whole experiment was specifically proposed to test the manufacturer’s claim that their special cable would have an effect on the digital outputs of a CD player.”

    IMHO testing this hypothesis would not be satisfactory to refute the manufacter’s broad claim that installing this lead will improve sound quality. If I were the manufacturer then I would simply turn around and say that although the effect on digital outputs is very hard to detect, it has much greater effect on other components and will still improve overall sound quality. I don’t believe that this is actually the case- I just don’t think testing this hypothesis is sufficient to refute the manufacturer’s claims.

  19. GWO said,

    February 14, 2006 at 4:10 pm

    testing this hypothesis would not be satisfactory to refute the manufacter’s broad claim that installing this lead will improve sound quality.

    True, but it would invalidate that the mechanism claimed by the manufacturer to improve sound. Which means, any improvement would be due to luck.

  20. Steve Phelps said,

    February 14, 2006 at 4:14 pm

    Invalidating the claimed mechanism doesn’t invalidate the effect!

    Just because light propogates as a wave-function doesn’t invalidate measurements of the speed-of-light made by people who thought that light was strictly a particle…

  21. Steve Phelps said,

    February 14, 2006 at 4:21 pm

    Ultimately I guess this is all futile though, because people with the audiophile/newage mindset will always retreat into claiming a hypothesis such as:

    “There is an objective effect that only manifests itself in the absence of a double-blind trial”

    Note that this is untestable and hence unrefutable. But just because it is untestable doesn’t mean that it is false. You can call it “pseudo-science” a la Popper- but name-calling isn’t going to change these peoples’ minds- (and remember that there are plenty of irrefutable statements in science that are perfectable sensible- I can see this sparking a flamewar though).

    Empirical evidence — or lack of — is never going to convince these people.

  22. Chris L said,

    February 14, 2006 at 4:52 pm

    “the effect on digital outputs is very hard to detect”

    The point is that this argument is technically invalid. Effects on digital outputs aren’t hard to detect. They’re very easy to detect. As has been discussed to death above, once you show that the stream of 1s and 0s is the same, it’s only things like jitter *at the DAC stage* that can make a difference.

    In any event, I completely agree with you that we will never change an audiophile’s mind with a test like this. The aim is always simply to shine a light on the truth, and try to prevent any fence-sitters from falling on the wrong side.

  23. Steve Phelps said,

    February 14, 2006 at 5:15 pm

    ok – let me rephrase that – how about “We find your results highly interesting. However, in the light of our own subsequent tests, the effect on digital outputs is relatively weak compared to the effect on other outputs, and can also vary signficantly from player to player, and also depends on the amount of interference already present in an installation, and so can vary from customer customer. Nevertheless we acknowledge that the effect on digital outputs is not as great as on other components, and therefore we now recommend to our customers that they prioritise other components such as the DAC, when upgrading their system.”

    Such a claim would be testable- but a lot harder to do so.

    I guess it makes sense to take things a step at a time though.

  24. Max said,

    February 14, 2006 at 6:52 pm

    Ok. So how about we rephrase the question. If we know what bits we lay down on a cd (by using a .bin and .cue file to burn the cd, which will introduce some FEC redundant data) we know exactly what the bitstream output of the cd should be (once error correction has occurred). Forgive me – I don’t know red/orange book all that well, so I don’t know whether the FEC gets passed through in the bitstream, but you get my jist.

    It would be sufficient to show that a CD player with any chosen lead yields back a bit for bit copy of the original to show that it would be impossible for any cable to have an effect (whichever one Ben chooses). Even if there is jitter in the signal, we will have demonstrated that that jitter has no effect in the data being passed to the amplifier (where of course our debate can start all again) which will mean that whether or not it is there, it will necessarily be inaudible (assuming the DAC in the amplifier is independently clocked).

  25. Max said,

    February 14, 2006 at 7:10 pm

    Further to that, as someone who is currently purchasing various bits of hifi kit and trying to discern the nonsense from the audible, is Ben aware of the claims made by e.g. What Hifi, who swear blind that separates stands make a noticeable difference? Whilst I can understand that speaker stands might (what with all the vibration), although I have never tested that so can’t comment, I refuse to believe (although I’d love to be proved wrong) that it could make an audible difference (as is claimed) to an amp or cd player (although audible differences on a record player are much more plausible) whether it is sitting on a shelf or a beautiful glass number.
    The claim that expensive vs cheap optical/coaxial digital cables could make a difference likewise seems nonsense to me (and apparently you should use coax over shorter differences to avoid the distortion caused by the signal being converted to light through the cable), but the one that really amuses me is the extremely expensive HDMI/DVI cables being offered (digital video).
    The fact that most of us spend half our day sitting in front of a hi-res monitor with an el cheapo DVI cable, sitting far closer than we ever do to a TV and have no complaints and yet suddenly notice the difference when sitting 5 times further away when using a TV seems most implausible of all.
    While on the subject, I’d be interested to know the differences in optical/hdmi output between cheapo and expensive cd/dvd players (which magazines swear by), but given the can of worms you’ve opened here, I think that might take some time…

  26. Rachel said,

    February 15, 2006 at 4:25 pm

    Dear All
    Am I missing something here? I have read the original article and lots of your terribly facsinating posts and still will not be calling in my kids for supper tonight using a dog whistle because they won’t bloody hear it!!! I shall use a bell and no-one will go hungry. I want to take part in the experiment at the “lower” end of the spectrum because I can’t even see the differnce in TV picture quality between the image received down a cable and that received via a digibox (and I have got mighty fine eyesight – 20-20 and all that). If my nearest and dearest spend a small fortune on some nobby cable so that they can imagine an infinitesimally small improvement in something that was perfectly fine anyway, someone else around here won’t be able to spend a relatively small amount of money on a piece of beautiful artwork for our hall which everyone will notice and say “Wow! That’s new and makes a huge difference to what were, previously, completely bare walls!” I look forward with eagerness to the post that seeks to convince me that buying a dog whistle is a good buy as a kid-caller because, although no-one will hear it, the noise really is there.

  27. Drew Stephenson said,

    February 15, 2006 at 9:10 pm

    I’m not going to advocate the dog whistle but it’s all relative; my landlady had a new fireplace put in and i didn’t notice for a week, i guess it just comes down to what’s important to you but don’t expect ‘everyone’ to notice a new picture on the wall… :¬)
    P.S. i’m not going to spend £75 on a kettle lead either

  28. Paul Richmond said,

    February 17, 2006 at 11:53 am


    If you use a dog-whistle to call your kids to dinner, at least you will be able to use the well-worn line “Your dinner’s in the dog”.


    How about testing the Russell Andrews kettle-lead to see if it can be used to make better tea or coffee ?

  29. Steve said,

    February 20, 2006 at 8:16 pm

    It seems like the general concensus is that HI-FI users are idiots who buy anything if they are told it will increase performance ?

    I thought hearing acuity was varied , and would have guessed that someone who spends a lot of time listening to music would be able to tell if there was a difference, more so than someone who spends all day with an mp3 player ?

    I suppose expensive audio is no better than a cheap midi system either, and that all CD players sound the same ? and if the signal is the same when it reaches the amp then all amps would sound the same ? and all amps draw the same current from the mains, and as speakers are driven by watts and drive units operate in basic terms by vibrating , then there can be no difference between them etc etc ?

    Regarding optic cable, I thought RCA could transfer more data than optical ?
    And an RCA connector is not all that good at preserving a true 75ohm signal.
    And most interference is generated from the mix of mains, interconnect and electrical equipment in close proximity to each other ?

    I would also have thought not all people into music would want to spend money on cable when they could buy more music, yet some feel the cables make a big enough difference to take them home and demo them, and choose one after listening buying what they thought sounded best.

    Its also interesting the amount of claims made about why cables should not make a difference, yet no one questions the acuity of the measuring equipment or can make there mind up on what it is about recorded music that means so much to some.

    If CD was so good why are manufacturers still trying to better it, it does not carry more information or recreate music more than analogue, and due to the nature of digital and jitter, are you sure every time you hear a CD it has the exact same errors as the first time ? or could it be that the measurements and engineering we are applying is too crude compaired to human hearing ?

  30. Ben Goldacre said,

    February 20, 2006 at 8:34 pm

    so, does anybody have a cd player that takes a kettle lead, or some license free music, in london?

  31. Tommy said,

    February 21, 2006 at 9:12 pm

    I have a CD player that takes a kettle lead, and a decent Hi-Fi too (a Quad system). I don’t have any license free music though…..

    I’m in Barons Court in London

  32. El_Cid said,

    February 24, 2006 at 12:56 pm

    As a person who is involved in selling high-end video and audio equipment, I’m personally very annoyed by many of these nonsense claims by accessory manufacturers.

    In practical terms I have learned that at the very highest end (Transparent Cable company sells a pair — One Pair — of speaker wires for $30,000 US) the point really is simply to allow very wealthy people to completely distinguish and dissociate their products and systems from the commoners.

    E.g., why go out and buy a $10,000 DVD player when you’re just going to hook it up with the same cables that a commoner could buy?

    But on the serious side of testing:

    (1) Many arguments by the “tweaker” community (an industry term for those people who think they can milk out more performance not through better actual main products but using accessory / pseudoscientific “tweaks”) say that these special power cables and wires and what not help bring out “more” sound from the recordings they are listening to.

    (2) Recordings are produced in studios using certain equipment.

    (3) The goal of a musical recording is to capture and mix / produce as well as possible the desired sound of the studio engineers and artists.

    (4) If your equipment changes, rather than reproduces their originally captured and produced recording, then you have ruined the product.

    (5) So by their very arguments, all these tweaking solutions are not better reproducing the original intent of the artists, instead (if anything at all is changed) they are creating something new and different than the recording actually purchased.

    (6) If this is the case, then the tweakers need to stop buying pre-recorded CD’s, LP’s, DVD’s, and SACD’s, and go to small live shows, and then tell the artists and performers that the sound is wrong and bring along lots of little gadgets to hang about the performance space to make the artists “sound better.”

    – PS: If you’re aiming for actual fidelity, bear this in mind: the studio engineers who produce the recordings to which you (and the tweakers) listen do not use $30,000 speaker cables or $3,000 power leads. They might use $100,000 mixing boards, but these actually do something and have the computing power needed to produce today’s mixes, but they connect their $100,000 mixer to a $800 speaker using a $20 speaker cable.

  33. Mick James said,

    February 27, 2006 at 9:08 am

    Digital has posed a huge problem for the high-end audio industry, as the components are clearly on the same price/performance curve as the rest of the electronics industry. So as long as they get decent speakers, and to some extent I suppose cables, then the audio quality experienced by the proles must be getting better and cheaper very fast indeed. As someone who spent £280 in 1979 on a crappy music centre, I wonder what an inflation-adjusted sum would buy me know, and how that would compare to the very best equipment available 27 years ago?

    What intrigues me is that (again, with reservations over speakers) the audio quality coming from from a reasonable component system or even a midi system may now have surpassed that from audiophile kit (look at what happens to Bose prices while everything else gets cheaper). Imagine how a maker of handmade valve-driven computers in cherrywoood boxes would have fared against Dell in the last decade. (but I can hear it now…the 0’s are more vacuous, the 1’s are more unified….).

    Somewhere I have a little book of audiophile nonsense from the analogue era which I’ll try to dig out. Highlights I recall are: disconnecting all the lights on your amplifier, only having even numbers of LPs in your room and using channels of mercury to connect your speakers. There was even one audio guru who claimed to be able to tell which channel your television was tuned to–even when it was switched off–just by listening to your hi-fi.

  34. John Manderson said,

    February 27, 2006 at 8:41 pm

    The ear is very easily fooled into thinking it hears some thing. The following story illustrates this.
    I used to to a bit of sound engineering for a few friends who had a group, I hasten to add that I do not consider myself as a sound engineer, jsust some one who roughly knows which knobs to twiddle.
    During the sound check the guitarist decided he wanted his guitar a bit ‘brighter’ so I gave him a bit more top, he decided that that wassn’t quite enough so I gave him the full monty, we both thought it was so bright that it hurt, so I backed it off and he agreed that the sound was what he wanted. No problems, except that a coupleof minutes later I realised that I hadn’t increased the brightness on his channel, but on the unused channel next to his.
    If you think that an expensive piece of kit will sound better than a cheap piece of kit then it probably will, provided you ‘know’ that you are listening to the expensive kit.

  35. Ben Goldacre said,

    March 22, 2006 at 11:05 pm

    sorry i’ve stalled on this, snowed under and couldnt get a cd player which took kettle lead, will do in next few weeks, in the mean time:



  36. Mike said,

    April 18, 2006 at 11:04 pm

    Why don’t you just use your computer as the CD player (I assume your soundcard can output PCM)? Google “bit-perfect”, and you’ll see that it’s not an uncommon thing to have a soundcard (the $20 Chaintech AV710 comes to mind) that outputs bit-perfect PCM signals. The bonus is that if you run the test with the cheap cable first, you don’t even need to get a expensive mains lead, since you can’t possibly get better than bit-perfect (given the procedure of the “experiment”). Hmm… it looks like you’ve already acquired one, though.

  37. Mike said,

    April 18, 2006 at 11:10 pm

    Oh … I’m assuming that these “kettle leads” fit into the same power jacks on computers. In my limited experience, both computers and audio gear use IEC inlets; it didn’t occur to me that it might not be the case.

  38. Nick Grant said,

    September 30, 2006 at 9:47 am

    Have really enjoyed skimming through this and following up some links but didn’t spot any mention of Backmasking which gives a very very powerful demonstration of the power of suggestion over what we hear. Good way to prove that the Voodoo people are right, blind listening doesnt work!!! You need to know what you will hear then it works.


    Is a good start and you can make your own experiments in minutes without expensive leads etc just by playing tracks backwards to people with and without the words showing. Stairway to Heaven backwards is the classic! I saw Simon Singh do this at Hay Festival. Played it backwards, asked if anyone could hear anything, no, anyone hear the word Satan? Couple of hands in big audience went up. Then played it again with words on the screen, wow! Just try it.

    Most web threads argue whether it was Led Zep or the Devil himself that did this, given the limited technology at the time :-). One lecturer at Leeds (from memory) tried it on his students but with different words.

    I have tried it on an opera singer and ‘tone deaf ‘ people with 100% result, no stats analysis needed with this experiment.

    My suggestion is that Hi-Fi shops should have a sign saying ‘this sounds great’ visible when demonstrating expensive kettle leads and oxygen free sexed cables, or they could do as now and just tell people….

    Problem I have is I want to buy a new amp and speakers, how do I avoid self and salesperson deception.

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