[quote user="jimwall"][quote user="fr0g"]This
Blind test results is interestinng...[/quote]
Yip, but like the other popular test carried out that is published on the web, however well meaning and sincere in spirit, it is fatally flawed. They have failed to control the single most important variable in any possible experiment that intends to test the efficacy of a product designed to improve the quality of the mains supply. A damn fine try, which if the mains supply had been dodgy and had been demonstrated as such would have been valuable. Without any evidence that it was, it unfortunately proves exactly nothing.
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I agree with your assessment of the trial. I believe that conducting trial properly is a science in itself. Most of us have not been trained to recognise the many pitfalls and experimental variables that exist.
It was interesting looking at the results however. 6 people out of 15 got higher then the 50% you'd expect from guessing.
Also it was interesting that 6 people got below 50%.
While this might be the result of only having 15 test subjects, it also could be that some people are better at hearing differences then others. It would have been interesting to take those 6 people who got higher then 50 % and test them over a series of weeks to see if they still score higher then 50%.
A similar approach could be taken on those that scored less then 50%. Can they hear a difference and have an inability to correctly attribute the difference or do they just have bad luck?
The test was a commendable attempt at trying to resolve a very thorny issue but to have any creditability such a test would need to be properly designed/carried out by an accredited body like the IEEE.