An ocarina is a “vessel flute” that resonates the sound inside an empty cavity. The sound bounces off the inside of the instrument’s empty chamber, creating more sound waves as the air moves in from the mouthpiece and out through the uncovered holes. Ocarinas commonly have between 4 and 12 holes on a single-chamber instrument, and range in materials from vegetable gourds, wood and metal to various forms of stone and plastic.
Determine the number of holes you want on your ocarina. Select the placement of holes according to your hand size and appearance on the empty plastic 16-oz soft drink bottle’s surface. Hold the bottle to your lips with your fingers on the upper side of the bottle. Check the natural placement of your fingers on the bottle to confirm the best placement of the holes.
Place the bottle round-side-down on your work surface. Draw the number of holes you’ve chosen on the bottle. Draw the first hole as far away from the bottle opening as possible while staying on the round surface of the bottle. Make each successive hole at least 1/2-inch away from any other hole. Continue drawing holes until you’ve reached your desired number.
Insert the #1 size art knife's extremely sharp point into the pen marking of the first hole. Cut around the hole carefully following the pen marking. Repeat for each hole.
Place the bottle to your lips with your fingers covering all the holes but one. Blow into the bottle. Repeat the test for each hole by changing your finger placement while blowing air. Trim any holes that sound like they need adjusting to correct their resonance.
Ocarinas produce their best sound when the finger holes are far away from the mouthpiece. Placing the holes away from the mouthpiece allows the air to resonate longer inside the instrument before it leaves via the holes. This produces better overall tone and the over-tone series that is part of the instrument's signature sound.
Size each hole according to your fingerprint's surface area. Each hole can be a different size as long as your skin surface stops the airflow completely on each hole. Consider that a hole for your pinky needs to be smaller than a hole for your middle finger.
Do not place any of the holes on the bottom of the bottle. Keep all the finger holes on the round surface so that the sound resonates evenly.