It is obvious that you are not an engineer. No engineer with any competence would validate accuracy with something as fleeting as aural memory. The correct way to do it is to monitor the output signals of the source with the probes on an oscilloscope and compare those signals to the signals on a second oscilloscope probe connected at the output terminals of the amplifier. At this stage in an ideal outcome the only difference in the signals on the oscilloscope screen should be scales. Beyond the amplifier the speaker serves as an electrical to acoustical transducer and the output of the speakers can be monitored as well with a calibrated microphone to put that signal on the same screen as the other two traces for comparison. That is how accuracy is analyzed, assessed and measured.
@carlos269 My diploma and I respectfully disagree.
We were talking about two different things, so I can see why you reacted in this manner. I was talking about how an audiophile might find a reference, without knowing anything about engineering.
To keep this short, here is an important quote from an engineer who headed the design section of HH Scott, Mr. Daniel vonRecklinghausen:
If it measures good and sounds bad, — it is bad. If it sounds good and measures bad, — you've measured the wrong thing.
I'm in his camp. I believe measurements can show exactly why some amps and speakers sound good and others not so much. I don't think there's a thing the ear can hear that our instruments don't pick up. But at the same time its really obvious that many doing measurements don't realize the implications of some of them and most of the time those measurements are not published.
So we still have audiophiles who believe we can hear things we can't measure.
Another aspect is also understanding the rules of human hearing perception, such as the simple fact that the ear uses higher ordered harmonics to sense sound pressure and so is keenly atuned to their presence. Being able to apply those rules in the design of audio equipment is pretty important IMO.