Quote Originally Posted by mtrycraft
All sound the same? Prove this silly assertion.

Maybe this is the first exposure to this paper? Maybe it is an embarrasing paper to use as a reference? Maybe any number of reasons.

I presume you are impressed by this paper?

His premis is in stak contrast to what speaker researchers have demonstrated about measurements correlation to what you hear and prefer. Oh well.
I would have been more impressed with a better controlled listening test. Did he feed the piano to each amp and compared them to each other or to the live piano? If to each other, then you can maybe all sort of reasons.
It sounds like you are referring to a study that claimed listeners genrally agree on what is a good speaker. That's something I will try to remember the next time someone pulls up next to me at a stoplight with his 2000 -watt subwoofer pumping out street-shaking bass.