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Re: "Objective" audio tests are not objective: An inside view on where objective audiophiles go wrong with their blind t

Posted by Richard BassNut Greene on January 10, 2007 at 09:34:44

In Reply to: Re: "Objective" audio tests are not objective: An inside view on where objective audiophiles go wrong with their blind t posted by tomservo on January 10, 2007 at 08:30:59:

Clearly you have accounted for a large number of things, which can make the test non-optimal. On the other hand, it simply can’t be denied that ones hearing, like all your senses are invisibly tied to what you already think.

RG
I didn't deny that. I doubt if any component from Pioneer, for one example, would get a completely fair audition from an audiophile who believed Pioneer was mid-fi junk. I have no desire to know the brand name of any component I'm listening to and I never ask -- why risk bias?
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This power of thinking is so strong it can cause medical problems to retreat about 1 /3 rd of the time (placebo effect), or even make people sure they can hear the improvement from some little marbles in a jar, little wood blocks or a “quantum” cd fixer sitting on top of the cd player.
RG:
Sorry but here I disagree.
No one knows why the pacebo effect works.
We generally know our immune system will solve most health problems during our lives. Most without any medical help. We don't know if we were completely cured by positive thinking, partially cured by positive thinking, or we were cured by our immune system doing what it usually does, while positive thinking had no effect at all.
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So you have the old science question “how can I measure this without perturbing the system under test?” and the resolution / certainty issue, which depends on at one extreme “if” your companies future is at risk on the results or at the other end, if your just curious to find out.
RG
You first have to measure inherent psychological bias by telling a listener you have changed something, when in fact nothing was changed. That has been done many times and we do see strong bias toward reporting audible differences when nothing changed.
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Then you have to measure the effect of small SPL differences with no equipment changes. People may report audible differences when the only change was making the stereo 1dB louder. That has serious implications for all A-B comparisons because volumes are rarely if ever matched in sighted A-B comparisons.
RG
There's almost zero chance two components will play at exactly the same average SPL unless A-B volume matching was done. Maybe interconnects would not need volume-matching -- I'm not sure.
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Tubeguys proposal is the logical direction to go, set it up at home, do it at your leisure when ever you feel like it.
The actual root point of all the blind testing after all is what counts, to remove prior knowledge of what which one you’re hearing.
RG
A-B volume matching is just as important

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Designing and building a switcher (easier for speakers than low level signals) that could pass scientific scrutiny (examination with a network analyzer to assure that electrically, it can’t effect the signal etc) is beyond the hobbyist and until one could be sure that invisibility was reached, the issue of “is the switcher affecting the signal” remains a dark cloud (and for skeptics, would always remain anyway).
RG
The instant switching does not replicate ordinary listening when there would be a one minute or longer delay to hook up a different component. Instant switching could allow a listener to hear a subtle difference that would not be audible if there was a multi-minute delay for component wire swaps. Why take that risk? Most times when we listen to our stereos there is a 24 hour delay from the last time we listened, not a fraction of one second.
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The up side for a push button switcher is that it is proven ones acoustic memory is detailed for only seconds and fades with time (references in an earlier post somewhere here).
The up side for actually switching the cables is that the switcher can’t affect the signal and costs no money to do, you just need a helper.
RG
The cable comparison is unique because you need two jumper cables to attach the switchbox to the amp. No one is going to buy extra pairs of expensive cables to cut them into 6" jumper cables ... so the jumper cables in use during a test will very likely be different wires than the cables being tested. Wire swaps are the best methodology for wire comparisons.
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It is important that the levels be adjusted to be the same, it is an old hifi salesman’s trick to raise the level of the speakers they were promoting by 1 dB relative to the others (back in the old days when stores had switchers to audition any amp with any speakers). That small amplitude difference was interpreted as being clearer, not louder. With electronics it’s easy to do, with speakers it is hard as they have so many different kinds of errors.
RG
It's puzzling that audiophiles usually claim to hear sound quality differences but never mention which component is playing louder than the other, when that is a measurable fact.
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In a way, to me, that makes these kinds of products pretty close to being a audio fraud or at least fully illusory like high fashion, Jewelry.

RG
Fraud is when a product does not do what is claimed. If you wanted to stretch the definition, almost every product is not as great as its advertising suggested. At least Brilliant Pebbles and Tice Clocks could be used for home decoration and telling you the time? I don't know what one would do with Intelligent Chips ... but one time an artist friend came to our party with jewelry she made from a computer circuit board. Well it looked like a big circuit boad hanging from a silver wire chain around her neck. I came out with a multi-meter and offered to test her circuits, but she saw me staring at her ample chest and kept away from me the rest of the night. I was only looking at her circuit board. Really.
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It is cool to see people talking about this, sort of cutting through a perceptual membrane, exploited by many, which all are fully accustomed to or even un-aware of.
RG
I miss the old subjective-objective battles that degenerated into pissing contests after one post. Meanwhile the surroundsoundphiles just shake their heads and wonder why anyone would want to listen to two-channel stereo.

Tom Danley

Richard BassNut Greene
Subjective Audiophile 2007

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