Cable Controversy Podcast

Well, it isn’t really a controversy, but I never was very good at headlines. Anyway, ages ago I downloaded a Quick Hitts Podcast entitled ‘Audio Insanity’, with a tagline of ‘You may think you’ve got a great audio system, but does your amplifier have LRF support?’ I won’t link directly to the podcast, since the producer really ought to get the, er, ‘hits’ on his own page, but you can download it from the page linked above. Just use your browser’s page search facility to find ‘Audio’ once you’re there.

It’s a pretty good coverage of the issue of whether high end cables can improve sound. As I discuss here, it’s a pretty doubtful proposition, although the most plausible is actually the cables discussed in this podcast: speaker cables. The only reason there is some plausibility is that the impedance of the loudspeakers and the output stage of solid state amplifiers is rather low. At eight, but perhaps as low as four or three at some frequencies, ohms, a few tenths of an ohm resistance in a cable can waste power. This is more so the case in home theatre than old-style stereo. In the latter, one would typically have the two speakers just a metre or so on either side of the electronics. In the former, you may have surround speakers six or seven metres away from the electronics on the back wall of the room, and the cables may be snaked through wall cavities, and consequently come to fifteen metres in length.

That’s why I usually recommend not Monster Cable (too expensive!), but the thick speaker cables from Dick Smith Electronics, which costs $AUS4.99 a metre. Just on general principles, just in case.

Back to the Podcast. The producer, Dave Hitt, discusses the Randi million dollar challenge and the $US7,250 Pear Anjou cables, which I discuss here. And what’s nice is that Mr Hitt actually has some experience in the field, and actually conducted his own blinded tests on cables many years ago. He branches out into a discussion of some of the more ludicrous hifi claims that are out on the Internet, none of which are surprising to those who have been following the field for a while.

One small correction. He remarks that a 3dB increase in volume level is the smallest perceptible.  Actually, it is closer to 1dB that is perceptible. For example, I estimated here a 1 or 2dB difference in level in the two versions of audio on the Pink Floyd live DVD, later largely confirmed to be 1dB*. In addition, most modern amplifiers with digital volume controls adjust the level by 1dB, although some are by 0.5dB, with each click. Many portable and general purpose devices use 2dB, which is a pretty good balance between quick action and fine tuning.

Still, Mr Hitt’s main point that very small increases¬†in volume which can’t be perceived in terms of actual loudness but instead act to simply make the slightly louder audio sound ‘better’, is perfectly correct. This is one of the things that makes A/B testing so difficult, since this effect can be apparent with volume level differences of just 0.2dB (just a 2.3% increase).


* I should precisely confirm this by measuring the output from the two tracks over a set section, but I’m too lazy for such a trivial point.

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