I have my flame suit on now so here's what I think.......
I believe that any stereo system is musical, why, because all sounds that a system can produce are capable of providing the audience with a pleasurable feeling tied to the music being played.
IMHO, Musicality or musical is not a very good descriptive term in relation to how a specific audio system is able to mimic the sound of the 'absolute sound'
. What i believe we are all trying to accomplish with our systems generally speaking encompasses two goals...
1) A sound that 'fools' us into thinking that we are in the presence of the performers that we are listening to, and
2) A sound that will allow us to relax and enjoy the performance, which is as close as possible to what was originally recorded onto the medium that we are listening to.
If you play an instrument or attend a live musical event, almost all of the sound that you are going to hear can be considered 'musical'. As an instrumentalist, I personally have a gauge as to how musical I am sounding on any particular occasion, but that isn't what's being discussed here