At a pottery fair in Pittsburgh, I ran into Kimberlyn Bloise, who makes handsome musical instruments that are also mugs, vases and pendants. They sound and look wonderful, and have the strange quality of something both charming and haunting, like remnants of a vanished culture. You can order them from her online shop.
I put a lot of testing into my instruments, but none of them plays a full scale, and none are traditionally tuned. The clay changes so much from when I begin to working with it to when I have the finished product. It shrinks and expands, and the pitches change along with it. What I have been able to do is figure out where to place the holes in relation to the size of the resonating chamber (the hollow handle) so that the notes all sound good together on each individual piece. The flute mugs all play parts of a blues scale! Could I figure out traditional tuning on all of them? Probably. But it would take so much planning and effort, and my prices would have to reflect that. I'm sure you've noticed that "real" instruments are quite expensive, and I don't want to make mine that pricey! Plus, I don't intend for anyone to play the flute handle in any professional capacity, so I don't sweat it too much.
Here's a flute hidden in a mug handle:
The large horn vase:
Here is the "complaining husky" horn vase:
And the bouncy udu: