Hi,
I get impression that in lot of modern music being musical is not a particularly big requirement for being a good composer. How I define "musicality"? Well, for me it's natural talent, natural ability to feel music, to understand it, to improvise, to create melodies in your head out of blue, without the need to construct them step by step by any scholastic method. A musical person is someone who hears a song once or twice and can easily play it on his guitar, or sing it rather well, or even improve it, add new elements, cover it in an original way. I think most/all folk musicians, especially in earlier times, in real traditional music were quite naturally musical. The same is true for most popular and classical composers.
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