Actually it was originally called a Steam Piano.  The
dictionary pronunciation is ka LIE uh pee.  The Carny
[carnival] pronunciation became KAL ly ope.

Several years ago while I was playing in Monroe, MI, a man came
to me, and in a thick accent said to me, "Why you call that kal
YO pee?"  I told him that I call it a ka LIE uh pee.

He said that's not what he meant. He looked at the side of my
trailer where the word Calliope is prominently visible and said,
"cal YO pee is Greek word and I am from Greece and I know this
word.  Why you call it that?"  I couldn't come up with a snappy
answer so I told him that is what it is called in this country.

Then he told me again, "That is Greek word and is pronounced kal
YO pee."

All I could do was nod my head in agreement.  After all, who am
I to argue Greek language with a Grecian man?

For what it's worth...

Hal Davis