How air temperature affects an ocarina's pitch
How air temperature affects an ocarina's pitch is pretty straightforward. Like all wind instruments their pitch is influenced by ambient air temperature. They play flatter in colder environments, and sharper in warmer ones.
When you blow an ocarina, the voicing mixes your warm breath with air from your environment, and the internal temperature stabilises between the two. Ocarinas are made so that they play in tune at a given temperature such as 20°C, which is called its 'tuning temperature'.
As noted. If an ocarina is played with the same pressure, the pitch will be flatter in colder situations and sharper in warmer ones. The pitch of an ocarina changes linearly at about 1 cent per degree Celsius (1.8°F),
Compensation for ambient air temperature variation
The pitch of an ocarina also changes with blowing pressure, and so you can compensate for the pitch variation caused by air temperature by blowing harder or softer. But this is a little more complex than it may seem.
If you have an ocarina give this a try:
- Finger a low note and vary your blowing pressure from low, until the ocarina squeaks, tracking the starting note and the highest note with a chromatic tuner.
- Repeat this same exercise on the highest note, again tracking with a chromatic tuner.
What you will find is the pitch of the high notes is much less sensitive to pressure variation than the low notes. Due to this irregularity, when playing in a colder environment, you have to increase your pressure more on the high notes than the low, and vice versa in warm environments.
Compensating for pitch means that the shape of the breath curve also changes, and the following graph visualises what is going on:
In this graph:
- Curve B represents the breath curve of a hypothetical ocarina at its original tuning temperature,
- the steeper curve C represents playing in a colder environment,
- and the shallower curve A playing in a warmer environment.
Particularly, notice how a small change on the low end requires a larger change on the high notes.
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.
The impact of ambient temperature on the pitch of an ocarina can be compensated for within a limited range. A variation of about plus or minus 15°C (27°F) from the tuning temperature is normally tolerable.
Pitch compensation is limited by the high notes as they are so much less sensitive to pressure changes. If an ocarina is played in an 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.
Do note that playing towards the extremes of available compensation will not produce an ocarina's best sound. It is recommended to get an ocarina tuned to play at a temperature close to the environment you intend to play it in.
Best sounding pitch
It is worth noting that as an ocarina's timbre changes with blowing pressure, you can not know how a maker intended an ocarina to sound unless you know what temperature it was tuned to play at.
If you do not know what temperature an ocarina was tuned to play at, best sounding pitch can be used as a basis instead. Best sounding pitch is just the pressure at which the high notes sound best in your opinion.
The high notes of most ocarinas sound best in quite a narrow pressure band. If blown 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.
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. Vary your breath up and down to find a point where the note has the cleanest sound. The pitch can then be measured with a chromatic tuner, and correlated with the temperature of your environment.