10 trials is not enough but 2x10 trials is. It is an equivalent to 20 trials within some time interval. You may sum it and get 8/10 + 8/10 = 16/20. This is perfectly valid in probability theory and one may find what 16/20 means. BTW, I have a further 8/10 result. Why not 16 or 20 trials in one row? Because it is difficult to keep concentration, the differences are really very small. The only important outcome to me is, that 20kHz cut
...'done the way I did it' ...
may lead to a tiny sound difference and such difference is not distinguishable to everyone. Our hearing differs, and this is the fact. Humans are not measuring instruments, try to digest it. I have already posted the link that summarizes studies on about 400 subjects that confirms that some subjects are sensitive to >20kHz components that are accompanying the audio sound signals. There are no trivial answers to trivial questions, though some would like to have them. This is a bit funny, to me. Get humble, if you can.
you seem to see and hear what you want to -- whether it's in your experiments, or in what you read. This is becoming clear. The Reiss meta-analysis is not definitive.
If you really want to be truly scientific, now is the time to start figuring out *what* is causing the audible artifact you're reporting.