OK, so here's something that's been bugging me. Around the Internet, certain male singers are described or have described themselves as Irish tenors, mostly very early recording artists like Billy Murray and John McCormack, who actually were Irish by descent and nationality.

Both of those singers have recordings uploaded on Youtube and when I listen to them, I get the impression of a classically-influenced but very nasally singing style. Is that actually what the term "Irish tenor" refers to in terms of singing voices or styles- a nasally yet "refined" tenor voice? Or is it something much broader than that? Billy Joel, quoted " here describes his "own" voice as "a pure Irish tenor like Paul McCartney". I don't hear anything nasal in Joel's voice, though he is a tenor.

So, what exactly is an 'Irish tenor'?