Data that is only relevant to the actual test. It cannot be extended beyond that. It is saristically impossible.
Now i am sure that an example can be found that proves that false, and if true in a particular instance the measurements, as interpreted by you, may be opposite of your expectations. As least partly due to the fact that am amplifier cannot be evaluated outside of the systen (which includes speaker (and cable connecting them))
dave
Yes, even if the test is properly executed with keen listeners, lack of a statistically significant result does NOT prove or imply that there is no difference.
It is only a null result, not proven. In my experience, this is often due to a poor system or poor set up. The better the playback system is,
the more differences can be heard through it.
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False. This clearly highlights a failure to understand the testing methodology. Not only that, but clearly overestimates one's own hearing resolving capabilities. If a difference is audible, it should be heard. If all differences are below the hearing threshold, it cannot be heard. If no audible difference is found, then no relevant difference exists in the absence of confirmation bias.
You have formed a straw man argument. It need not project anything beyond the intention, which is to determine the existence of any difference. If we remove their sight and knowledge of which amp is playing and suddenly all claims of differences disappear, then there are none. Follow up tests and cross referencing the results will support that where there is no perceived difference, the electrical differences reside below the threshold of audibility.
Can you support this, or is it conjecture? You need to clarify your statement, in particular why you claim that the results are germane only to the system. It would appear that you misunderstand the limits of hearing and how ABX tests operate.
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It is clear that you donot understand the limits and limitations of an ABX test.
Conjecture in the sense that i have seen the results but don't care enuff to spend the time to dig it out.
An amplifier, a speaker (and the connecting cable) are a system that cannot be completely evaluated outside of the system.
A simple example is that a voltage amplifier will sound crap with a speaker designed to be used with a high output impedance amplifier and vica-versa.
Ugnoring that THD measures are largely irrelevant, i have seen data where a low THD NAD amplifier driving a set of speakers had higher total system distortion than the system had a much higher measured THD SE amplifier installed.
dave
Sorry, you are quite wrong on this. A null result proves nothing. Please consult your Statistics 101 book.
Also, the playback system used for the test places major constraints on what can be heard.
All good scientists are well aware of the limitations of their equipment.
I've always found it amusing when inexperienced researchers prefer a low bandwidth current probe
because it makes the waveforms look so much prettier. After a while the better ones learn otherwise,
that better tools allow deeper results. Those who don't tend to end up in sales. Not that there's anything wrong with that.
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You have formed another circular straw man argument. Not only am I quite versed in ABX testing, but also its applications.
Then you have no argument and your claims are invalid.
You clearly overestimate the important of the wiring. Does wiring constitute a portion of your product lineup?
Can you provide evidence of speakers that have been specifically designed to operate with high impedance output stages along with results that have been verified through measurements and ABX testing?
You need to explain how the total system distortion was verified. Was this done using a distortion analyzer, or what it sighted listener opinion? Was the amplifier being used within its designated design parameters, and equally important, how did the distortion compare with driving a different load? You have not provided information regarding the native distortion characteristics of the amplifier in question.
The common problem among subjective opposition to ABX testing, and yours, is that it's formed upon the premise that two amplifiers of varying provenance and sufficiently low distortion, when normalized to have identical output levels in the same environment, will somehow be distinguishable from one another. This is in clear ignorance that below -75dB, distortion is undetectable, and that response variances of less than 0.1dB are also undetectable. To date, among countless ABX tests spanning more than 30 years, there is no credible research evidence or peer reviewed doctrine to support your claim. The results of such tests have always been that where measured differences reside below audibility, no difference can be heard. This of course has left many an audiophile with bruised egos and resentment for their own earlier statements. ABX is after all, a listening test of whether a subject can hear a difference.
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Again, a null result in a scientific test does NOT prove anything, other than that the test is possibly inadequate.
Denial of this fact shows a misconception of the scientific process.
Not that there's anything wrong with that.
The falsehood belies your presumption that not being able to tell the difference must point to a fault in the testing method. The salient problem in your claim is that you ignore the facts of the scientific methodology behind ABX test. What you incorrectly allude to as a null result, is actually one of only two possibilities. Either the listener can hear a difference, or they can't, and successive follow up tests weigh into the final result; A null result is the indicative that the listener could not detect any difference, despite his claims that he could. This in itself proves that the differences were below the threshold of audibility and that no sonic difference was apparent. You have no argument.
Is your name David Clark? Not that there's anything wrong with that.
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May well be, but your defense of invalid conclusions show a lack of understanding.
Just because i am unwilling to spend the time to do research for you that you should already have done?
Just being complete. Wire is not in our product lineup.
I do it all the time. With an amplifier having variable output impedance each loudspeaker has an optimal setting.
Yes.
That is not relevant. An amplifier cannot be truly evaluated outside the system it is used in.
You are putting words in my mouth. I did not imply any such thing.
Can you prove that?
So what. ABX is only capable of proving things are different. You are making an invalid conclusion.
dave
That you believe this clearly shows that you do not understand the process.
Believe what you want, i'll just go enjoy my hifi.
dave
Yes, there are a fair number of people like this around here, and I'll bet most of their audio systems sound like crap. Not that there's anything wrong with that.
Yes, both their audio systems and their belief systems lack merit. It's like a closed system.
S
seanconnolly
I have already done the research. I am merely making note of your misrepresentation and salesmanship. You entered the discussion at your own peril with full knowledge of the consequences, and the onus is on you to support your claims in the public eye. Your chameleon attempt to mimic a valid argument is evident of your unsatisfactory circular debating method. Ignoring the obligation to actually address others’ specific inquiries in favor of simply reeling off perceived attributes about individuals does not support your case, but rather erodes any retreating credibility.
Thank you for complying with an answer.
It would be useful to know the speakers and what is the method of impedance manipulation is in use. An output transformer, adjustable feedback, or something else?
Results are required for verification. It is too easy to say that one is not interested in sharing them with readers. Inquiring minds here and abroad are watching and waiting patiently.
You should explain the reason why you believe this to be so, and what particular detractors you perceive to act against those results. As it stands, this appears highly presumptuous.
Nor was I writing to you. Re-read the post more carefully this time and do take note of to whom it was addressed.
Yes. The smallest variance in frequency response, that which is detectable in music, is currently accepted to be 3dB in musical content and 1dB in tone recognition tests. 0.1dB is far lesser than any of these. The accepted threshold for harmonic audibility is about 1%, equal to -45dB. In more complex content, this is masked and further reduced, according to literature. Harmonic masking is fundamental to the basis for compressed music playback, where distortion is used to fill in missing frequency bands. The modelling of such was remarkably complex, but has benefited from years of study and modelling. Minus seventy-five to eighty dB is accepted as the threshold for both harmonics and noise in controlled listening tests, but levels closer to -45dB are commonly found to be prevalent. Thus, -75dB is inaudible. I'll update as my scans come in, as there are far better references available.
Floyd Toole: "There is some evidence that we can detect slopes of about 0.1 dB/octave, which translates into a 1dB tilt from 20Hz to 20kHz - not much. Such a spectral of error, is likely to be quite benign and subject to adaption."
The Acoustics and Psychoacoustics of Loudspeakers and Rooms.
"A change by 1 dB is about the smallest change a human being can detect."
Sound
Auditory Perception of Nonlinear Distortion, Audio Engineering Society, Geddes, Earl R.; Lee, Lidia W.
AES E-Library Auditory Perception of Nonlinear Distortion
Audibility Perception of Nonlinear Distortion, Audio Engineering Society, reprint 5891.
James Moir, Just detectible distortion (JDD) "level can be no lower than 1%, ie -45dB"
D.E.L Shorter, "Just perceivable distortion values of 0.8% to 1.3%".
P.A Fryer, 2% - 4% distortion
Von Braunm ü hl & Weber, 1% - 2% at frequencies > ~ 500 Hz
Harry F Olson, JDD level of .7% using 40 Hz to 14 kHz bandwidth test system
M. E. Bryan & H.D.Parbrook also embarked on tests involving the audibility of harmonics.
Just Audible Thresholds for Harmonic Distortion, By Bryan, M.E.; Parbrook, H.D.
Just audible thresholds for harmonic Distortion: ingentaconnect
Audibility of linear distortion in loudspeakers, Sylvain Choise
http://www.almainternational.org/ya...audibility_of_linear_distortion.106172825.pdf
https://secure.aes.org/forum/pubs/conventions/?elib=16446
Measurement of Harmonic Distortion Audibility Using a Simplified Psychoacoustic Model. By Temme, Steve; Brunet, Pascal; Qarabaqi, Parastoo
Your complete disregard for scientific doctrine is quite vile, to say the least. To state that the work of scientists spanning 30 years is invalid is utmost pompous and presumptuous. It is possible that you may have been misled to believe that ABX tests always results in a null test. That is not the case. If a difference is audible, the listener has at their disposal, the full arsenal of their own cognitive processing and hearing to select the proper selection. If they can hear a difference, they are capable of getting the test correct with a high degree of reliability. When differences are great enough to be heard by the subject, that is reflected in the results. ABX test results are also used in screening, sometimes leading up to blind testing. Infinity used this latter method in controlled tests to keep an edge over the competition. They had quite a rig for it, a giant rotating turntable that would cue up the next set of speakers for the listening subjects.
Addendum: If two electronic audio devices with identical frequency response and identical (or sufficiently low) distortion have ever entered a real valid ABX test and were found to be readily distinguishable from each other, let us know. It could be written with confidence that the scientific community at large would be interested in knowing.
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This is getting boring. I do not disregard science. I do object when someone uses ABX to contend that devices are the same when it is statistically impossible for it to prove that
You said that not me. What i said is the when 2 devices that are determined to be different and one clearly better, that the measurements of the DUTs may not come out the way you think. The "poorer" device may be the winner... simply because the measures we typically use are inadequate. Useful when you are developing something but useless in quantifying what something sounds like.
dave/signing off from this thread
Judging an amplifier by sound is like judging a chili cookoff.
Everyone's got their own different opinion of what sounds good, or what tastes good. Everyone has their own preconceived notions on what constitutes a good amplifier or chili - feedback in an amp is like beans in chili for some people. The story behind the product and the 'secret sauce' in it opens up hours of debate.
And in both cases, listening to people talk about it is tiring, and after a few hours you really don't want to be around those people anymore.
Everyone's got their own different opinion of what sounds good, or what tastes good. Everyone has their own preconceived notions on what constitutes a good amplifier or chili - feedback in an amp is like beans in chili for some people. The story behind the product and the 'secret sauce' in it opens up hours of debate.
And in both cases, listening to people talk about it is tiring, and after a few hours you really don't want to be around those people anymore.
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