How air temperature affects an ocarina's pitch

So that people can play together, musical instruments are tuned to a standard called concert pitch. Ocarinas are no exception, but there is a catch: their tuning is affected by both pressure and temperature. Like all wind instruments, the pitch produced by an ocarina is temperature sensitive. The voicing mixes your warm breath with ambient air from the environment and the internal temperature stabilizes between the two.

The pitch of an ocarina is sensitive to blowing pressure, and pressure also influences timbre. Thus, when an ocarina is initially made, each note is tuned to sound at the desired pitch, using enough pressure to produce a good tone. The pressures generally ramp up towards the high notes, and together are called the breath curve. The catch is that the pressure needed to sound any of these notes also varies with temperature.

When an ocarina is made, it is tuned to play in concert pitch at a given temperature, such as 20°C. I call this the instrument's tuning temperature. Playing in a warmer or colder environment raises or lowers the pitch, if the same pressure is used. As the ocarina's pitch is also affected by blowing pressure, you can compensate for this by raising or lowering your breath. However, the pitch of the high notes are much less sensitive to pressure changes.

If you have an ocarina, this can be observed easily. Finger a low note and overblow it until the ocarina squeaks, tracking the starting note and the highest note with a chromatic tuner. Next, repeat the exercise on the highest note; you will not be able to push it anywhere near as far. Because of this irregularity, when playing in a colder environment, you have to increase your pressure more on the high notes than the low. Consequently, compensating for pitch means that the shape of the breath curve also changes.

The graph below visualises this effect: the orange curve represents the breath curve of a hypothetical ocarina at its original tuning temperature, the steeper red curve represents playing in a colder environment, and the green curve playing in a warmer environment. Particularly, notice how a small change on the low end requires a larger change on the high notes. This means that there is less compensation as the airstream becomes turbulent. If your environment is considerably colder than the ocarina was tuned to play in, the high notes will squeak before you can push them into concert pitch.

Should you have also read the page on breath curves, you may have noticed that the graph is the same as the one that I used to demonstrate the breath curves of high and low pressure ocarinas. I am not being lazy; they are actually the same thing. Tuning an ocarina to play at a higher pressure requires blowing harder, and thus requires a steeper breath curve. Compensating for a cold environment also requires an increase in pressure and has the same effect.

How to deal with this as a player is covered on the pages 'Playing the ocarina in tune' and 'Dealing with warm and cold environments' but, in summary: to reliably play an ocarina in tune in different environments, you have to internalise how the breath curve changes in these situations. You also need an ocarina tuned to play at a temperature close to the environment you intend to play it in. Pitch can be compensated for within a limited range and the pitch of an ocarina changes linearly at about 1 cent per degree Celsius, so a range of about plus or minus 15°C from the tuning temperature is normally tolerable. This is limited by the high notes as they are so much less sensitive to pressure.

If you don't know an ocarina's tuning temperature, you can instead measure its best sounding pitch. As an ocarina's high notes are fairly insensitive to pressure changes, there is a limited pressure range wherein they sound best. The best sounding pitch is the pitch at which they subjectively sound best in your current environment. To find your ocarina's best sounding pitch, play one of its high notes, such as the high E or F on a C ocarina. Notice that when you blow too softly, the note will sound weak and airy, while blowing too hard makes it airy and harsh. Pushing the note further will cause the ocarina to squeal. Vary your breath up and down to find a point where the note has the cleanest sound.

Do note that what you subjectively judge as best can vary from what a maker intended, as pressure influences timbre. See: 'Playing the ocarina in tune'.

Thoughts on...