geoffkait - 25 trials? Are you crazy? That’s a lot more trials than even The Amazing Randi demanded. And he never lost a blind test challenge. Why? Because nobody can sit there and pay close attention for 25 trials. Not even for ten trials. Gimme a break. What a ripoff! If the differences are of the subtle variety nobody can pick the correct one many times in a row. That’s the scam. Capish?
@geoffkait
I agree in principal that listener fatigue can influence the test. The wiki article I’ve indicated indicates "QSC recommended that no more than 25 trials be performed". Twenty five is fair. There needs to be a high enough number (25) and high enough confidence level (95%) to ensure the person under test is not simply "guessing" their way through it. Please forgive me for not wanting to give my money away.
Keep in mind, it remains theoretically possible that regardless of however many tests are involved, the person under test can guess them all correctly. Also, as I’ve pointed out many times, I can tell the difference between Amy > Bob regardless of however many times you play them, regardless of how quickly or slowly the duration between the songs are, regardless of the test type, regardless of time of day, temperature and ANY other circumstance. Therefore, those who claim a "major" and "not so subtle" difference when the impossible is stated, realistically should also be able to demonstrate such claim under any condition. Further, because it is conceivable the person under test can guess correctly or in fact can demonstrate the impossible, there is a chance I would loose. This is a chance I am willing to take. Capiche?
EDIT:
I forgot to mention that if anyone is unhappy with the terms, they are at liberty to decline and write "no thank you". I do recall my writing on more than one occasion, "there is no obligation" to prove anything.