What is meant exactly by the description 'more musical'?

@mglik You are right but everyone uses the same hearing perceptual rules. Its a sort of common denominator.

Over time, as a designer you gain experience knowing how the distortion profile looks as compared to how it sounds. It gets to the point that you can predict how the equipment will sound if you have enough of the relevant measurements in front of you. 

There is that old saw about trust your ears not the measurements. That was really true until sometime in the late 1980s or early 1990s. Sometime in that period it became possible to measure the things that really tell what an amplifier (or preamp) might sound like. The knowledge that this is so is scarce, as is the understanding of the significance of some of the measurements.

At any rate, if the design issues I mentioned so far are not observed in a design, it is very likely it will not be deemed 'musical'. It might surprise you, but we've never relied on tuning any of our products by ear. We rely very heavily on measurements. Only after we get what we are looking for do we give it a listen. So far this technique has served us pretty well.

measure and listen = ….. theres even a switch for that on ( only ) the Ayre DAC. IMO it’s really the only approach if the goal is more than flavorizing or worse, blind ( deaf ) objectivism….

I mostly agree on same perceptual rules…until we encounter pitch perfect individuals….

@atmasphere   I’ve noticed than many of the newer vintage of class d amps have extremely low distortion… but still have rising distortion vs frequency often starting around 2khz.  Is it correct to speculate that these amps, whether GanF, Hypex, purifi,  etc. would sound more musical if the distortion increase could be pushed beyond 10 khz rather than just 2khz?

but still have rising distortion vs frequency often starting around 2khz.  Is it correct to speculate that these amps, whether GanF, Hypex, purifi,  etc. would sound more musical if the distortion increase could be pushed beyond 10 khz rather than just 2khz?

@snapsc Yes.

"Musicality" is clearly not a technical term - how could it be? Of course that applies to a lot of audiophile jargon, to varying degrees. 

Best to keep it simple. I think it usually means "I really like this", or in the context of direct comparisons, it can be applied to one component to put the other component down "softly" - rather than a flat out "I think that one sounds bad". Unfortunately most of us spend too many words skirting around what we REALLY think of something.