Double blind test- over a month- could this be a reliable test for any equipment?

@mzkmxcv, actually for me 10 seconds is optimistic for perfect auditory recall. I can keep the tone but the rest goes vague fairly quick.

Perfect visual recall goes even quicker. Almost instantly I'm left with a Van Gogh impression.

Nice, but hardly photographic...

Yes, let's make ourselves even more anachronistic by putting our heads down back into the sands of subjectivity. Down with blind listening tests! Not our reality. 

On the other hand we can be grateful that aeronautics, automobiles, broadcasting, computing, engineering, healthcare, and satellite navigation don't follow suit!

Audio is not life and death, so there is nothing seriously wrong with following subjective impressions, but only as long as you remember that - that is all they are - subjective impressions.

On the other hand if you are looking for truth, then the scientific method is a better way. One that has been adopted by the civilised world for centuries.