I like to search for ocarina related things on the internet from time to time. You never know what you’re going to find, and it’s a good opportunity to learn or discover something new about the ocarina. I wanted to share this tip I found for practicing in Quiet. I’m not sure if it actually works or how well, but here it is. Excerpt below.
Wanna Blow an Ocarina No One Can Hear?
HERE is a contribution that can be extremely useful. It is possible for an ocarina to be played without disturbing anyone. How you ask? Simply by playing it inside a felt hat. Opposite edges of the brim are held together with a safety pin. Next, the ocarina is placed inside the hat. Then the hands go into the openings. As for the mouthpiece, the most favorable method is to let it protrude through a hole made in the top of the hat. I tested this arrangement with a soprano in G, and the loudest tones were almost completely blotted out. Any old felt hat should be large enough for most ocarinas. – R. J., Elgin, Ill.
You can see the publication on google books here.