I have no problem with controls and. One that's used from time to tie might be something like a 2 ohm resistor where a person should reliably be able to pick it out. Also, training is never a bad idea. But this begs the question, just what training ought be done to verify some of the claims that have been made? Claims like something sounded darker, more organic, airy, well you get the picture. But if null results can only apply to ine set of circumstances, what is one to make of sighted comparisons that don't even try to do rigorous level matching? Now if DBT's are not the end all, than what can one propose in its stead? In your situation, have you come across something that clearly made a difference but you had expected it not to?
"I've found that when you want to know the truth about someone that someone is probably the last person you should ask." - Gregory House