Maybe this is also already there. But, I could not find an answer easily. Let's say a very good amp designer is designing an amp. If he is after measurements, I guess it will be easier for him to tune the prototypes. Measure the prototype, trace back for the issues and make necessary changes until you get the desired measurements. Now lets say a very good designer is designing an amp by considering both measurements and subjective feedback. Now the people who give the feedback will be telling things like "this lacks body" or "sound is too thin" or "weight is not there" or a combination of things like this. Now, how can the designer change that feedback to something like, "this resister should have a different value" or "this component should be changed" or "the bias here should be changed"? Is there an elaborate answer than "experience" for this question?