Recognising badly tuned ocarinas: how to measure the breath curve
When you're evaluating ocarinas, one important factor is to check that the instrument has been tuned well, as it affects how enjoyable your learning process will be. If you play a scale, the pressure should ramp up gradually between notes, with no sudden and arbitrary changes.
The two following graphs exemplify the breath curves of a well tuned ocarina, and an (exaggerated) poorly tuned one.
The pressure curve is created when an ocarina is made by tuning sequential notes slightly flat, requiring you to raise your pressure to compensate. We can check how well the ocarina is tuned by measuring these tuning differences:
- Finger any note.
- Blow as steady as you can, holding the note in tune.
- Without changing your pressure, raise the finger for the next note in the primary major scale. Do not tongue the transition, as doing so can change your blowing pressure.
- The tuner will show that the higher note is playing flat. Note down how many cents it is flat by at the exact moment you lift your finger.
The cent is a unit of measurement for musical intervals that allows very precise comparisons to be made. It is defined as follows:
- 100 cents = 1 half step (semitone)
- 1200 cents = 1 octave
To measure the breath curve of your whole ocarina, begin at your ocarina's lowest note and check each note sequentially, writing down the note and how flat it falls. It is critical that you do not change your blowing pressure, as that will give you a false reading.
Breathing in the correct way, and also the response latency and update rate of the tuner you are using, have a notable impact on how easily you can measure the breath curve. Those things are discussed later in the article, but for now, we will move on to understanding your results.
Understanding your results
Once you have measured the pitch changes across the range of your ocarina, understanding the results is a matter of looking at the difference between sequential values. In a well tuned ocarina, the changes should be about regular across the entire range, like this:
- C: 20
- D: 21
- E: 19
- F: 20
- G: 20
- A: 21
- B: 18
- C: 20
You may notice that the changes increase or decrease gradually between sequential notes, which may be done to shape the breath curve. A gradual reduction towards higher notes, for example, creates a more linear breath curve, as the base curve is exponential:
- C: 20
- D: 19
- E: 18
- F: 17
- G: 16
- A: 15
- B: 14
- C: 13
Any large irregular changes, such as a sudden pressure increase followed by a decrease, is a tuning error. In practice, it would look something like this:
- C: 20
- D: 0
- E: 40
- F: 60
- G: 10
- A: -10
- B: 50
- C: -30
When is a tuning error a problem?
Whether an error is a problem depends on how bad it is:
- 5 to 10 cents is not normally noticeable.
- 30 or more will be difficult to compensate for when playing at a moderate tempo.
- Larger errors can be objectively considered bad tuning.
I advise double-checking your result as it can be difficult to hold your breath perfectly constant at first. I also recommend taking a few measurements and averaging them.
Do be aware that the exact magnitude of the changes between notes will vary with temperature. That is covered on the page 'How air temperature affects an ocarina's pitch'.
Traps, blowing technique, and the impact of tuners
There are a few easy mistakes that can cause you to see one reading, when in fact the reality is something different, including your subconscious mind, blowing technique, and the behaviour of certain chromatic tuners:
Subconscious pressure changes
In normal playing, you learn to change your blowing pressure subconsciously as you change between notes. Normally, that's not an issue, but if it happens while measuring the breath curve, it will appear that your ocarina has a perfectly flat breath curve (zero cents between notes) when in fact it does not.
Learning how to hold your pressure constant deliberately is critical:
- Ensure that you are using belly breathing (see next heading).
- Practice playing long tones, holding your breath constant over the duration of a full breath.
- Finger your ocarina's lowest non-subhole note, then switch to the same note an octave higher without changing your pressure. The ocarina will sound very thin and airy.
- Repeat this exercise for notes that are closer together, such as low C and G.
It can help to use a different blowing technique for measuring than the one you use for playing. For example, ramping your pressure up to the first pitch without tonguing.
Also, pay attention to how it feels in your chest when you are exhaling at different rates. This can help you notice when you are changing your blowing pressure.
You may wonder if it is possible to measure a breath curve by increasing your pressure as you would while playing. That does not work very well, as the human body cannot control blowing pressure deterministically.
The best you could achieve would be to measure the difference in the breath curve between an ocarina you've played a lot, and another one. You wouldn't be able to know the breath curve of your main instrument, and readings would probably wander over time.
Using good blowing technique
Using a good blowing technique makes it much easier to blow with consistent pressure and get accurate measurements of your ocarina's breath curve.
People can breathe in two distinct ways, called shallow breathing and diaphragmatic breathing. To get the best possible control, you really need to use diaphragmatic breathing, and how to do this is explained on the page 'Blowing an ocarina correctly'.
Using a good tuner
Finally, it is worth noting how the tuner you are using can affect your results. There are three factors:
- Tuners often average pitch over time, a feature called 'needle damping'. Needle damping makes it impossible to get an accurate instantaneous reading, as it smears changes in pitch out over a longer period of time.
- Chromatic tuners do not measure pitch continually, but rather sample it periodically. By analogy, this is like if you were observing someone in a sound-proof room, but only opening the door for a few seconds once a minute. It would be impossible to tell what they are doing when the door is shut. A tuner with a low sample rate will not show you slight fluctuations in your breath, and thus won't show what is actually happening.
- Most chromatic tuners display cents using an analogue dial instead of a numeric readout. This is not ideal, as numeric readouts are easier to read quickly.
The characteristics I'd recommend looking for in a tuner are:
- High sampling rate.
- Low latency.
- Little to no needle damping.
- A numeric cents display in addition to, or instead of, a needle-based readout.
Such a tuner makes measuring your ocarina's breath curve far easier. The only tuners I know that meet these requirements are software tuners such as APTuner.
