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Old 23rd August 2011, 08:11 PM   #101
SY is offline SY  United States
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Quote:
Originally Posted by ThorstenL View Post

BTW, would you suggest that the failure of one person to detect one particular effect in very specific circumstances offers proof that there is no difference than can be perceived by anyone?
No, and no-one claimed that except you. Especially because Lipshitz was able to distinguish by ear and said so- did you actually read the article?
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Old 23rd August 2011, 08:12 PM   #102
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Quote:
Originally Posted by fireworks View Post
How is the switching done usually ? Is it by means of a relay ? If so, is it a special type of relay designed for audio, or a regular relay suffices ?

I believe that there is no problem for an audio amp to suddenly have its output switched from 8 ohms (or so) to no load ("infinite" impedance).
Are there problems with that ?

What other details are important for the power switcher ?
Relays have been used. Manual cable swapping has been used. Heavy duty rotary switches have been used.
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Old 23rd August 2011, 08:16 PM   #103
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Quote:
Originally Posted by SY View Post
Relays have been used.
I am interested in the relays used: are they regular relays or special ones for audio ?
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Old 23rd August 2011, 08:19 PM   #104
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Depends on the level. I don't know what ABX Corp used- my preference at speaker level was mercury wetted, but it's been a lot of years since I ran those sorts of tests at speaker level. For line level, I use a Cinema Engineering or Shallco rotary switch.
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Old 23rd August 2011, 08:22 PM   #105
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Hi,

Quote:
Originally Posted by auplater View Post
So... with all the hub-bub as to the invalidity of most (if not all) objective efforts to characterize reality from illusory perceptions proffered by a vocal minority here, one wonders what we are to make of the subjective evidence presented by many non-believers as to the superiority of their claims??? Seems all the objections to the ABX/DBT protocols and multivariate analysis schema are exponentially confounded in subjective claims of superiority based on pronouncements made w/o evidence other than personal observational skills... how's about putting some numbers and such up, eh?

John L.
You may wish to occasionally make use of the return key.

Bad science is bad science.

And in this debate one side makes claims that are not supported by credible evidence but with idle and empty (and may I add unnecessary) claims that are bad science, while the other counters those claims with equally bad science, but carefully cultivates a false appearance of being scientific.

In fact one side is bad as the other and jointly they have been a major force against rational evaluation and research in audio.

My objection to ABX as promoted the ABX Mafia is purely based in statistics. They use very poor statistics. Poor science. Repeatedly criticied, but never corrected. But that is to be expected from those who have little use for truth.

I referenced several JAES (hence peer reviewed) articles dealing with this. In addition there are further major issues around experimental desiign for the specific tests promoted by the ABX Mafia.

Of course, that it just me and my views do get into the way of a jolly good scrap.

Ciao T
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Old 24th August 2011, 05:35 PM   #106
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First of all:

Quote:
Originally Posted by SY View Post
I'm sorry, I think this is profoundly wrong. Replicability is true for a limited number of things, but there are many things for which it's not.
This was your response after my post (excerpt) in the blowtorch thread:

"And normal scientific practice would require sucessful replication of the experiment by other groups, which is of course a bit more difficult compared to other fields as we need a human detector."

So, please answer my question if you mean "replication" or "repetition" .


Quote:
Originally Posted by SY View Post
Citing a paper and implementing multiple comparisons are two different things. They didn't do the latter. Perhaps HF content can work for brain waves of dead fish?
Let me correct it a bit, the occurence of multiple comparisons is the problem, the cure is to incorporate a _correction_ for the multiple comparison problem.
On page 3552 the authors mentionend to take countermeasures for the multiple comparison problem:

"To account for multiple non-independent comparisons,
the significance of the activation in each brain region detected was
estimated by the use of distributional approximations from the theory
of Gaussian fields in terms of spatial extent and/or peak height
(Friston et al. 1994)."

For multiple independent comparisons they could have used simply the Bonferroni-correction.
From where did you get the impression that they did not use a correction at all?

Quote:
The "sensory" comparisons were a model of bad statistics. Take a set of results that average out to 50%, separate them into two piles with one larger than 50%, one smaller, then claim significance.
Maybe you should read Scheffe´s article and some other papers on this topic to avoid this sort of statements.
And the other cheap shots don´t make it better.

Quote:
The results of the replications at NHK and KEF were not "inconclusive," they were null.
You should know that there were several other papers dealing with this; the results of two papers from different authors were (for example) :
-) HF should never be reproduced through an additional tweeter
-) HF should always be reproduced through an additional tweeter

That´s why i wrote "inconclusive" .

The guys at KEF (btw we do not know really a lot about this one, do we? ) and NHK did perform really different experiments and therefore i am not that surprised by diverging results.
Especially because due to Oohashi the sample length could have an important impact.

That´s why i wrote "inconclusive" .

If nobody tries to repeat Oohashi´s experiment this will remain in the dust.
Thorsten_l. is absolutely right, Oohashi presented extended follow up research which confirmed earlier results and gave some hints for possible explanations for the results .
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Old 24th August 2011, 06:27 PM   #107
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See Benjamin and Hochberg 1995 J Roy Stat Soc B 57 289 to see how the analysis should have been handled.

I'm quite familiar with Scheffe. Their data handling is not correct.
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Old 25th August 2011, 08:33 AM   #108
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A couple of comments:
I saw this in one of this thread's references -
"Yet another interpretation of the first story is that the anxiety produced by listening to the unknown decreases the sensitivity of the listeners. That anxiety can raise sensory thresholds is well-proven."
I wouldn't dismiss the article outright, but I have to wonder why they wrote that. "The unknown"? We're not talking poltergeists bumping around in the attic here. It's some headphones. This seems like they've designed a milquetoast detector, not a DBT. I mean, come on.
So later on I spy this article on subconscious, involuntary thought. Something brought up in discussions here. Again, I wouldn't cast it all aside, but the article states this:
"People will respond to questions more conservatively if they're standing near a hand sanitizer, which signals a possible threat."
Maybe I'm missing something, and I'm not the troll. But this sentence is total nonsense to me. Is mysophobia that common? Is this how you gild a turd? Should I feel threatened by hand sanitizer? This unknown anxiety is killin' me..
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Old 25th August 2011, 08:49 AM   #109
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All this talk about anxiety affecting results, training the listeners being required, etc would make more sense if the common response were "I can't hear any difference; they both sound the same."
However, isn't it usually the case in ABX tests that the listeners think they hear a difference, believe that they hear differences and can identify known components, BUT that the data shows they cannot tell the difference at all?
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Old 25th August 2011, 11:15 AM   #110
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Quote:
Originally Posted by VictoriaGuy View Post
However, isn't it usually the case in ABX tests that the listeners think they hear a difference, believe that they hear differences and can identify known components, BUT that the data shows they cannot tell the difference at all?
Usually? No. Listeners are able to hear many differences in those tests- when the differences exist and are audible. When the differences do not exist or are not audible, they don't. See my earlier bibliography. What Stereophile (who has a strong commercial interest in avoiding controlled tests, ABX or no) never explains is why this "anxiety" doesn't seem to inhibit listeners from recognizing subtle changes like level, frequency response, phase, distortion, clipping, noise, polar pattern, dynamic range, data compression...
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