I recently wrote an article for Pottery Making Illustrated on troubleshooting tone-production pitfalls in ocarinas, because any potter who has ever been stymied by a malfunctioning fipple deserves help. It's available online here. It's acoustically and musically serious, while simultaneously including lots of googly eyes.
The article had a word limit that I was already exceeding, so I left out my number one rule of ocarina making:
Fipple ain't broke, don't fix it.
There you have it. Now go forth and make music.
