Listen to each with a curtain hiding them over and over, could be this, could be that, and then no more discernable difference.

If you could listen to both at the same time, and process the difference between them I wonder if that difference wouldn't fade over time.

It follows then that A-B doesn't work for the same reason break-in is mostly a bubba meintza, we quickly get used to the sound of a component and that sound is brain-processed into one that is pleasing.

Of course, the premise is probably faulty........