Now now Susan-Marie an 'un-natural use of your voice'? More likely simply an unfamiliar use of your voice. Using higher notes may mean more practice but its no more un-natural than placing your fingers in weird places on a piece of wood with strings across it. With practice it becomes natural. And you needn't fear for your ear drums just your windows. I once heard a soprano soloist sing a high F purely and well sustained, it felt like it was ringing right through my middle.

I am a soprano, so I get edgy about these things. Looking at that chart of voices I sing from the alto up to the soprano range without warm up, most of my singing though is in the mezzo range. Whenever I sang with my husband's family, a bunch of altos (the women that is), I ended up frustrated because once I was warmed up my voice had nowhere to go and I was nervous experimenting with harmonies up there where its so exposed. Now I've learned some songs which they can sing lower harmonies to and we all have a better time.