The highly disciplined, truck driving, pavement pounding, nail banging, Civil War buff (His self-renovated fixer-upper even dates back to 1865), and proud papa of three debunks popular music mythology: classical musician does not equal jazz artist. Adam Unsworth, French hornist with The Philadelphia Orchestra since 1998 embraces the jazz idiom with the same guile and gusto as he does everything else in life. At age 10, Unsworth confided in his first horn instructor, a professor at the local U …