"Musical" is only a qualitative attribute statement coming from an EXPRESSED subjective experience with a word used to pointed to it as "good experience" ...
It is not a logical statement we can described as in a logical analysis as an argument...Except when marketting conditioning ask to us to compare two amplifiers for example..
When i say the soundfield is "musical" i do not refer to a marketing argument about an electronic component compared to an another one, because there is then no OBJECTIVE ACOUSTIC argument in a comparison between isolated components or the different possible coupling with other components IN AN UNCONTROLLED ROOM .. Electronic components and even speakers to be analysed optimally and more objectively must be put out of a living room in an industrial laboratory or in a room acoustically dedicated to them with the right synergetical components coupled with them ...
In acoustic experience saying that a speakers/room is "musical" refer to specific ACOUSTIC conditions and principle which will make by a balance between many OBJECTIVE acoustic and psycho-acoustic factors and their optimal ratio an OPTIMAL "musical" experience for all people and not for only some person taste as the choice between electronic components may be in isolation from each another or coupled in a acoustically UNCONTROLLED room ...
"Musical" then become less a mere subjective attribute and more an objective description now by virtue of acoustic mastery of the speakers/room relation by an acoustician or by someone who try his best to control room acoustic...
There is "petition of principle" using the term "musicality" only when we spoke of the musicality of one component compared to another TO SELL THEM , but the falsehood here is that what is good for some ears in a living room with specific components will be less good for other ears who will prefer other components in the same living room...To determine which set of components is really better we must acoustically control a SPECFIC room where they will be embedded and compared together... And even then a room must be acoustically control FOR A SPECFIC COMPONENT to make it shine.. It is why it is difficult to compare which of two amplifiers is the better in the absolute, or between speakers, it is difficult because the room acoustic setting will change our impressions of them ...
There is also a scale in the quality of electronic component design which can make us prefer a 10,000 bucks amplifier instead of a 500 bucks one simply because one isbetter designed in quality parts and in complexity and efficiency...
Acoustic can make a difference between components which are not too far from one another in the electronical design quality scale...
But when the speakers/room relation is under relative control, as kota said, then musicality became more and more a quality acoustically determined by many OBJECTIVE factors ... It is why great hall acoustic is an ART of listening based on acoustic science...The ratio ASW/LV is objective and can be controlled precisely in acoustic laboratory experiments but his perception is subjective, it is psycho acoustic..
Then what "musicality" means in electronic marketting competition has nothing to do with acoustic listening experiments in room/speakers under acoustic controls in general, it is two different jobs...
For sure we must pick good designed component first, but once the choice is made we must design the room controls to make them shine in an acoustical "musical"or acoustically balanced way ...
It is why the dictum among acousticians is true : "No speakers can beat their room"
Translation: no electronic component can beat acoustic control even speakers...
In audiophile experience the easiest thing to do, so hard it seems to be, is picking the right component first , the hardest thing to do is putting them after the purchase in the right acoustic optimal conditions..
And there is also the mechanical and electrical embeddings but it is another story, and the acoustical embeddings control is the most important and the more hard part of the job to set right...