Cable claim grading

I’ve been in contact with the Australian Skeptics about its $100,000 prize for proof of paranormal abilities.

No, I don’t have any such abilities.

What I am hoping is that they will extend eligibility to at least some of the weirder claims in the audiophile community. They are now considering this.

But I thought it might be a good idea to grade the level of plausibility of one category of claims: that different cables can affect sound quality in discernible ways. Obviously, and trivially, they can. A working cable will quite definitely sound different to one that has been severed. So the discussion must be restricted to cables in good operating condition, designed for the particular task. A cheap ten metre HDMI cable may well not carry 1080p60 video. But this results in obvious problems (signal dropouts, or even a complete loss of signal).

So, from the highly implausible to the totally ridiculous:

Loudspeaker cables: Clearly, loudspeaker cables can make a difference in the gross sense that really thin, high impedance cable can waste some of the power which should be used to drive loudspeakers. For example, if a long run of extremely thin cable had a resistance of one ohm, then it could waste up to 20% of the amplifier power at some frequencies with some loudspeakers (ie. those frequencies at which the loudspeaker impedance is at 4 ohms). This is rarely a problem these days since good quality low impedance cable is available for a couple of bucks a metre. Nonetheless, this is clearly a matter of degree. So the question is whether a human can distinguish at all the very subtle effects imposed by an expensive loudspeaker cable, compared to a modestly priced one. (Let alone whether those effects can legitimately described with the overblown descriptions often employed.)

I note that Randi has previously permitted such tests for the JREF $US1,000,000 prize. Nonetheless, if someone were able to reliably tell the difference between two sets of loudspeaker cables, under proper test conditions, then the likely explanation would be one due to a special sensitivity on the part of that person. I’m not sure whether I would admire or pity such a person.

So I don’t think that this should qualify. (I write this reluctantly, because I would like to use it to challenge such claims.)

Analogue interconnects: These are the stereo cables used to connect, for example, a CD player to an amplifier. These have the ability to affect sound quality also, I suppose, but this ability would be at least a couple of orders of magnitude below that of loudspeaker cables. The latter have to deliver a signal from an extremely low impedance source to a moderately low impedance load. Interconnects have to carry a signal from generally a high-ish impedance source to an always high impedance load (47kOhm is the norm).

A/V Digital interconnects: such as optical and coaxial digital audio, and HDMI. Here we’re talking about a stream of digital bits at reasonably high voltage, and so the signal is already pretty damned robust. To the extent that they fail to carry a specific bit, some error correction kicks in. Where redundancy fails, sample interpolation takes place. If a bit is missing entirely, then the results are not subtle. They can manifest as a click in the sound. They won’t — can’t — have airy-fairy effects on the ‘musicality’ of the sound. Anyone who can demonstrate a reliable, repeatable ability to pick between two competent cables used in these roles in a proper double-blinded test is demonstrating a psychic ability.

USB: which is becoming increasingly common. USB signals are extremely robust. They must be because they are an important way of communicating non-audio digital data, such as programs, photo files and so on. In these other formats, not one single digital bit can be permitted to go awry. When was the last time you had a corrupt file due to copying to or from a USB hard drive? Even hundreds of gigabytes of data are sent over regular cheap USB cables to hard drives and other devices at extreme speeds without a single bit of corruption. Cheap USB cables find digital audio a doddle. And if they didn’t the effects wouldn’t have that ‘airy-fairy’ effect on the ‘musicality’ of the sound. Anyone who can demonstrate a reliable, repeatable ability to pick between two competent cables used in these roles in a proper double-blinded test is demonstrating a psychic ability.

Power Cables: I have written about this particular insanity before. If you are pretty clueless about technical matters, you can fall into the trap of thinking that speaker cables, analogue interconnects, digital interconnects and USB cables might affect the sound. After all, in one way or another it passes through them. But the sound goes no where near the chunk of cable you used to plug your amplifier, or whatever, into the wall socket. And there is no way that anything that a (suitably specified and working) power cable does to the power supply would be detectable in the spikey, wavery, mess that we call our power system. Anyone who can demonstrate a reliable, repeatable ability to pick between two competent cables used in these roles in a proper double-blinded test is demonstrating a psychic ability.

Not that it’ll stop them from trying. The Australian Skeptics Challenge Coordinator drew my attention to this review of a $1,000 plus power cable. Yes, some 2,800 words of crap, opening with the claim that this cable’s performance somehow has something to do with Richard Feynman’s conception of quantam electro-dynamics. Feynman, possessor of one of the greatest minds of all time, and a man with little tolerance for loose experimental procedure, would be made furious by what follows.

But, apparently, this power cable is ‘is patently superior to the [$595] Original in every way’. And since the improvement of ‘the Original over OEM cords … was literally mind boggling’, the author should be confident in undertaking a proper blind test between the $1,149 Signature cable and a $5 regular one.

Somehow I don’t think he will, even if he can win $100,000 from the Australian Skeptics, or $1,000,000 from the James Randi Education Foundation.

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7 Responses to Cable claim grading

  1. treblid says:

    Cables do make a difference when I restrict the freqs from 5hz to 90hz (ala sub woofer cables). Tried monoprice cable and one other (both <$30) and the monoprice ones are clearly inferior… Do I get the $100k? Because that will really come in handy. Full range and it's a lot harder for me to pick.

    But no ghosts are involved though (so can it still qualify?). I'm still in mixed minds about the power cables though. Same with USB or HDMI cables for that matter. Have a read at stereophile: http://www.stereophile.com/content/listening-96

    I have an open mind, but even that is hard….

  2. Stephen Dawson says:

    Ah, a link to unmitigated crap. Just call me, to use the author’s own words, a ‘technocodger’ launching into a ‘paroxysm of puritanical indignation’. He says: ‘When you listen to recorded music, you are listening to your household AC, and better AC equals better playback. That sounds obvious to me and you …’ on the assumption that ‘you’ won’t include the likes of me.

    But it is bull. You are not listening to your household AC. God! Every gadget in your playback train works on DC, not AC. Yes, you plug them into AC, which they transform down to a suitable operational voltage, and which then they hammer the shit out of in a rectifier (usually a bridge rectifier using four diodes in an artful arrangement) and a regulator (generally consisting of a sufficient number of capacitors for the needs of the circuit), turning it into DC.

    In some circuits, a degree of ‘ripple’ is permitted (ie. the DC voltage varies a little at double the mains frequency), but all competently designed audio equipment where the supply is feeding an amplification circuit, or some other voltage dependent circuit, hammers even harder until there is no ripple. If HF was on the mains line, it is long gone.

    And all of that has nothing to do with power cables anyway. How the hell can a couple of metres of large gauge cable damage the power? Or magically fix it?

    If the author of that piece, Art Dudley, is able to reliably and repeatedly distinguish between the sound of his or any system with competent power cable A and competent power cable B, I’ll happily give him, and you, five hundred bucks out of my own pocket. It will be worth at least that much to me for the lesson. Randi would give him a million.

    I’m interested how the two subwoofer cables differed in their results. I usually try to put in words like ‘competent’ when writing these things, but I think I may have forgotten, at least with regard to analogue interconnects. Indeed, some cheap analogue interconnects are not competently made. That is, instead of having proper shielding, they simply run a second conductor down the side of the active one.

    This is a particularly dangerous practice with subwoofer cables, since much of the strongest EMF in a modern home is at mains frequency — 50 hertz here — which is smack in the middle of a subwoofer’s operating band, and since subwoofer cables are usually much longer than normal interconnects.

  3. Fredrik says:

    Stephen, I absolutely agree with you on the value of (double) blind tests, or, to put it another way, the questionable value of non-blind tests. But I also think we need to keep an open mind here, and investigate these matters further, rather than just saying that “it’s impossible that this or that audibly affects the sound.” I remember reading about a very credible guy who runs a well-known audio store who was blind tested by his friends in another store. He could not only tell two interconnects (in the US$1000 price range) apart, he also correctly claimed that one was made of copper and the other of silver! Yesterday, I also read an interesting article by Chris Connaker at computeraudiophile.com. While testing Asus sound cards, he believes he has achieved bit perfect playback that still sounds awful.

    So, all of this was just a way of saying that there’s certainly a lot of marketing hyperbole and shallow test procedures out there, but that shouldn’t stop us from investigating and learning more.

  4. Stephen Dawson says:

    Hi Fredrik. Absolutely there needs to be a degree of openness in our thinking. It is always possible that some new phenomenon will be found, leading to a necessary rejigging of our understanding of how things work. For example, the Michelson Morley experiment of 1895.

    But what we have in, say, the case of power cables, are claims made in the absence of any credible evidence, and any even vaguely plausible mechanism. For double blind testing to be valid, it needs to be rigorously conducted with a jaundiced eye to both intentional cheating and inadvertent signalling. It is not easy.

    Here’s a very recent article in The New Yorker — http://www.newyorker.com/reporting/2010/12/13/101213fa_fact_lehrer?printable=true&currentPage=1#ixzz19SXuXddz — (h/t http://wmbriggs.com/blog/) outlining the problems with replication of studies conducted with what was thought to be the highest scientific rigour. Some 50%, perhaps more, of published studies turn out to be incapable of confirmation!

    So the first step for these claims to be taken seriously is for them to be carefully tested, then tested again by others. At the moment, all we have is people’s vaguely described impressions along with some double talk about something irrelevant (double helix wire arrangements! quantum electrodynamics!) I’d want to see the methodology on the ‘credible guy’.

    Meanwhile, the claims in the power cable articles linked here, and in the USB cable articles I’ve mentioned earlier, and indeed for various tweaks such as Peter Belt’s nostrums, are of a similar standard to those claimed by homeopathy practitioners and psychics. And invoking quantum mechanics as an ‘explanation’ is also disturbingly similar to what those woo merchants do.

    Couldn’t find the Chris Connaker piece at the website. Do you have a specific link?

  5. treblid says:

    I have the Xonar Essense (STX version). I do agree that card sounds awful under Windows 7 (posted this on DTVForum). It is supposed to attain bitperfect using ASIO, but using foobar (with ASIO output), it just sound normal if not outright terrible.

    Under Linux though and it’s a totally different story, it is good enough for me. The same hardware, but different operating systems. If Win7 is supposed to be bitperfect, I much prefer the flawed linux presentation.

    Which begs the question, is it about what you personally like, or what manufacturer think you like?

  6. Mark says:

    When do you think these con-artists, I mean business men will start claiming aspects of dark energy/matter as the reason their cables are better?

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