Intro
Have you ever wondered why some notes seem harder to sing than others—or why your voice cracks under pressure? The answer might lie in something called phonatory threshold pressure.
Welcome to The Voice Science Podcast, where we dive into the science behind all things singing and teaching. Here, you’ll learn how the voice works and discover practical tips to train it more efficiently. I’m Josh, the founder of voicescience.org. I’ve been educating singers and teachers for the last 13 years.
In today’s episode, we’re taking a deep dive into the science of phonatory threshold pressure—a fascinating concept that explains the minimum air pressure needed to make sound. We’ll break down what it means, why it matters, and how it connects to vocal efficiency, vocal warm-ups, and vocal fatigue. Let’s get started!
Definitions of Phonatory Threshold Pressure
So, what is PTP? And why should we care?
I first ran across the term Phonatory Threshold Pressure, or PTP, during my master’s while reading Ingo Titze’s book Principles of Voice Production. I read the 2nd printing from 2000 but it was originally published in 1994. Phonatory Threshold Pressure is the minimum pressure required to start and sustain phonation in kilopascal (kPa). PTP is an important concept for understanding vocal efficiency – something all of us want.
Most people aren’t very familiar with Pascal or kilopascal. So for a little more context, 1 Psi, or pounds per square inch, is equivalent to 6.89 kPa. A small amount compared to the 45-80 psi typically found in residential water pressure or the 30-42 psi in car tires. But even for the respiratory system 1 kPa is a tiny amount of pressure, according to a 1993 study by Fiz trumpet players can generate 23 kPa of exhilatory force!
How is PTP calculated?
To calculate PTP, we use a formula that considers the note you’re singing and your average speaking pitch. For example, if I want to sing A440, my PTP is about 0.95 kPa. But for a woman with a higher speaking pitch, it’s almost half that—around 0.46 kPa. This shows how individual factors, like your natural speaking pitch, influence the pressure your voice needs to sing.
Okay, so from this we know that the minimum amount of subglottal air pressure to start and sustain a note changes by individual and that we can make some general assumptions based on that person’s average speaking fundamental frequency. How does this actually help us?
If you’re curious about your PTP, I’ll include the formula in the episode notes so you can calculate it for yourself!
So now that we know what PTP is, why should singers know anything about it?
How does PTP actually impact singers?
Have you ever tried to sing a note, and nothing came out—or it sounded creaky? That’s likely because your subglottal pressure wasn’t high enough. Now, on the flip side, have you ever cracked on a high note? That’s even more common. In this case, you probably had too much pressure, and your vocal folds couldn’t keep up, so they shifted to a partially open position to release the excess pressure.
A great exercise is to try and find how little pressure it takes to sing a note. Pick any note, a note in an easier pitch range for you will be easier, but don’t let that stop you from being bold. Sing that pitch on the vowel of your choosing and try and sing it where it kind of just creaks out, increase the pressure just a little until the note stabilizes, it will be quiet.
Misconceptions about breath pressure:
More Pressure is Better – More subglottal air pressure can lead to increased loudness, and in fact is even required to sing louder. But while more pressure can help you sing louder, it often leads to tension, vocal fatigue, and even injury if overdone. And with microphones being used in most genres, the focus should be less on sheer volume and more on the quality of your sound and your vocal health.
Pushing more air is the only way to sing louder – This one seems rather intuitive since we know that increased subglottal pressure can make you louder, but it turns out this is only one way. To a pretty reasonable extent, you can increase the intensity of your singing by increasing brightness through the use of ring or twang which increases the intensity of harmonics in the 2-5 kHz range. Instead of relying on brute force, think of twang as an efficient amplifier for your voice—it lets you sing with more power and brightness without pushing harder. We’ll dive more into ring and twang in a future episode, so stay tuned!
A quick mental exercise if you are not driving a car or operating heavy machinery. I want you to think about a time you were told to use more air while singing. Think about how your voice felt, was it easier? Was it harder? It could have been either one, the point is that more air is not always the answer.
Recap and Takeaways
Today, we explored the fascinating concept of phonatory threshold pressure, or PTP—the minimum amount of air pressure needed to start and sustain sound. We broke down what PTP is, how it’s calculated, and why it varies between individuals based on factors like speaking pitch. We also discussed how understanding PTP can help singers avoid vocal fatigue, improve efficiency, and troubleshoot issues like cracking or failing to start a note.
We debunked common misconceptions about breath pressure, like the idea that more pressure is always better or that pushing more air is the only way to sing louder. Instead, we touched on alternatives like using resonance and twang to amplify your voice efficiently without overworking your breath support.
Finally, I shared a practical exercise to help you experiment with your own PTP and discover just how little pressure it takes to sing a stable, clear note.
Outro
Thanks for tuning in to The Voice Science Podcast! If you found today’s episode helpful, share it with a friend, teacher, or fellow singer who might enjoy it. Don’t forget to subscribe, so you never miss an episode.
Next time, we’ll dive deeper into the science of ring and twang—two powerful tools to enhance your singing with less effort. Until then, keep experimenting, keep learning, and keep singing. See you next time!
Elliot, N., Sundberg, J., Gramming, P., 1995. What happens during vocal warm-up? Journal of Voice 9, 37–44. https://doi.org/10.1016/S0892-1997(05)80221-8
Titze, I.R., 2000. Principles of Voice Production, 2nd printing. ed. National Center for Voice and Speech, Iowa City, IA.