Amir,
As an audio equipment reviewer, why do you choose not to actually listen (with music) to every audio component you review?
Note that I already understand (from your prior post) that you do listen to speakers & headphones. I'm wondering why you limit actual listening tests to those and don't bother to listen (again with music) to amps, dac's, etc.
Speakers and headphones as you know have big differences from each other. Furthermore, I can use blind testing of EQ to verify measurement accuracy.
With headphone amps, I push them to limit to see when they get distorted. Once there, there is no debate there.
With other classes of devices, impairments get very small to non-existent. No ad-hoc sighted test is going to be reliable and produce defensible claims. The only believable data would be controlled, double blind testing. I simply don't have the time or resources for this type of testing. So measurements plus psychoacoustic analysis stand in as substitute.
I do listen to this other class by the way in my everyday enjoyment and work. A headphone amp or speaker/headphone is driven by DACs. I do not find them to have any coloration or distortion. Stuff subjectivists report are like fantasy to me. I have probably 100 to 150 DACs here (no exaggeration). I have yet to fire one up and say, "oh, the soundstage has changed, bass is this and that, etc." This is of course backed by measurements and psychoanalysis measurement.
For people who claim there are differences in this class of equipment, for once, they need to perform an AB test without their eyes and with enough trials to provide reliable results. If they can even identify the difference, I will give them a cookie. :)
Our brain is a wonderful thing in the way it can adapt and change how it works. It can work without analyzing fidelity, or be told to focus into the smallest detail. The latter is what happens when audiophiles are testing gear. Such focused analysis results in hearing things that were always there, but discarded by the brain. It is NOT the result of the gear being different. Once this concept is understood, there won't be requests for "why don't you listen with music."
Among essentially transparent gear, I identify the ones that are best engineered. Much of this gear is also extremely economical, providing a perfect selection for your systems. That is, if you believe in audio science, engineering and how one's perception works.
Let's say for a moment the above is not true. And that there are audible difference. Why would you trust what I would have to say about it? Why do you trust anyone? Is your room the same as theirs? You play the same music? Your ears are the same? You see the problem? This is myth piled on top of myth that anything reliable is stated in subjective evaluation of audio electronics.
BTW, professional reviewers were tests with speakers in blind controlled tests. They did very poorly and could not even produce reliable let alone correct assessments!
Notice how reviewers were worse than audio salespeople!