July / August 2018
Editor's Lead In
Sound Magicians
What's the difference between a cable demonstration at a hi-fi show and a magic trick?
It's the bit where the magician says abracadabra!
Editorial By Greg Borrowman

  'Trust your ears' is a popular catchphrase in audio, particularly amongst subjectivists, who don't think that frequency response, power output, signal-to-noise ratios and other scientific measurements can tell them anything they need to know about sound quality.

However, even objectivist audiophiles — those who do think that power output, signal-to-noise ratios and other electronic measurements — can tell them things they need to know about sound quality also say 'trust your ears' because they know that measurements can't tell them everything they need to know.

But can you really trust your ears? I'm sorry, but the answer is no. You can't trust your ears. You can't even trust your eyes.

Think about a magician doing a stage trick, say with an empty hat and a white dove. You're shown the empty hat, and that there's 'nothing up the sleeves' then the hat is spun around and a dove flies out.

That's pretty much what happens at many cable demonstrations. I recall my first cable demonstration, as shown to me by a dealer in Far North Queensland. He had a small box that switched between what he told me was standard speaker cable and the expensive US-made brand of cable he was selling. The difference in sound was amazing. His cable sounded so much louder, more open and clean-sounding than the 'standard' speaker cable. The set-up had been provided to him by the Australian distributor, which had received it from the US manufacturer.

On investigation I found that the US cable manufacturer's cable run from the box to the speakers was around two metres. The run of so-called 'ordinary' speaker cable, however, was something like twenty metres long. Also, it wasn't 'standard' speaker cable at all (which in those days was 240V 10-Amp lamp flex) but bell wire — two single strands of thin copper wire designed to take 12 Volts D.C. to a front door-bell. Strangely, the dealer didn't see anything wrong with this set-up. 'It proves that cables make a difference', he said.

More recently, the cable demonstrations I have attended have used a more subtle trick, which takes advantage of the fact that the human ear has a built-in preference to prefer the louder of two otherwise identical sounds. So if you want to prove that one cable sounds superior to another, you just make sure that you increase the playback volume slightly when demonstrating the cable you want to sell. I can tell you for a fact that this is the methodology used, because while sitting in the audiences at hi-fi shows I have heard — and measured — the differences in sound pressure levels as the cables were switched.

'But the guy didn't touch the volume control in the demo I saw!' I hear many readers exclaim. No, but did you actually watch exactly which way he switched the input source selector? One trick is to use two cables from the source component, each connected to different line level inputs on the amplifier, and insert added resistance to the input you want to produce the quieter sound. Easily done and impossible to detect unless you open the amplifier. And if the amplifier has its own input sensitivity trim circuit, you don't even have to modify the amplifier to pull this trick. What about cases where the demonstrator didn't use the input selector, only the mute button? Then what you didn't see was him adjusting the volume using an R.F. or other type of remote volume control.

Because I can tell you that just as doves don't fly out of empty hats, volume levels do not change when you use different cables. 

[I am not the only person to have made surreptitious measurements during a cable demo. Mark Waldrep (AIX Records) recorded an entire cable demo and analyzed it. You can read his story about it at this link. 

Postscript: As a result of Waldrep's measurements and his post, he was kicked out of the Los Angeles and Orange County Audio Society and, presumably, will not be allowed to exhibit at future AudioCon events, which are run by the society. You can read about him being booted out at this link. 

--- Greg Borrowman

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