The type of clay would not really matter, as long as it sets rigid and does not have cracks.

Of course the item will be a lot stronger if the clay is fired.

They could also be made from ornamental gourds, or any other firm, hollow material that is rigid. Other possibilities include an old light bulb (but probably too fragile!), papier mache, or even a closed glass jar or bottle, with holes suitably drilled with diamond equipment.

The shape is rather immaterial. It is the VOLUME along with the size of the holes that are acoustically significant.

Any 1 no where there is online song books besides songbird.com?
ive practically memorized all those songs