How voice training changes the tongue in chest versus head voice

Jiu Song – jiusongjd@gmail.com
Integrated Speech Research Lab
University of British Columbia
Vancouver, British Columbia, V6T 1Z4
Canada

Additional authors:
Jaida Siu – jaidasiu@gmail.com
Jahurul Islam – jahurul.islam@ubc.ca
Bryan Gick – gick@mail.ubc.ca

Popular version of 1aMU8 – Effect of years of voice training on chest and head register tongue shape variability
Presented at the 187th ASA Meeting
Read the abstract at https://eppro01.ativ.me/web/page.php?page=IntHtml&project=ASAFALL24&id=3767562

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Imagine being in a voice lesson, and as you try to hit a high note, your voice coach says, “suppress your tongue” or “pretend your tongue doesn’t exist!” What does this mean, and why do singers do this?

One vocal technique used by professional singers is to sing in different vocal registers. Generally, a man’s natural speaking voice and the voice people use to sing lower notes is called the chest voice—you can feel a vibration in your chest if you place your hand over it as you vocalize. When moving to higher notes, singers shift to their head voice, where vibrations feel stronger in the head. However, what role does the tongue play in this transition? Do all singers, including amateurs, naturally adjust their tongue when switching registers, or is this adjustment a learned skill?

Figure 1: Approximate location of feeling/sensation for chest and head voice.

We are interested in vowels and the pitch range during the passaggio, which is the shift or transition point between different vocal registers. The voice is very unstable and prone to audible cracking during the passaggio, and singers are trained to navigate it smoothly. We also know that different vowels are produced in different locations in the mouth and possess different qualities. One way that singers successfully navigate the passaggio is by altering the vowel through slight adjustments to tongue shape. To study this, we utilized ultrasound imaging to monitor the position and shape of the tongue while participants with varying levels of vocal training sang vowels across their pitch range, similar to a vocal warm-up.

Video 1: Example of ultrasound recording

The results indicated that, in head voice, the tongue is generally positioned higher in the mouth than in chest voice. Unsurprisingly, this difference is more pronounced for certain vowels than for others.

Figure 2: Tongue position in chest and head voice for front and back vowel groups. Overlapping shades indicate that there is virtually no difference.

Singers’ tongues are also shaped by training. Recall the voice coach’s advice to lower your jaw and tongue while singing—this technique is employed to create more space in the mouth to enhance resonance and vocal projection. Indeed, trained singers generally have a lower overall tongue position.

As professional singers’ transitions between registers sound more seamless, we speculated that trained singers would exhibit smaller differences in tongue position between registers than untrained singers, who have less developed tongue control. In fact, it turns out that the opposite is true: the tongue behaves differently in chest voice and head voice, but only for individuals with vocal training.

Figure 3: Tongue position in chest and head voice for singers with different levels of training.

In summary, our research suggests that tongue adjustments for register shifts may be a learned technique. The manner in which singers adjust their tongues for different vowels and vocal registers could be an essential component in achieving a seamless transition between registers, as well as in the effective use of various vocal qualities. Understanding the interactions among vowels, registers, and the tongue provides insight into the mechanisms of human vocal production and voice pedagogy.

Vowel Adjustments: The Key to High-Pitched Singing

May Pik Yu Chan – pikyu@sas.upenn.edu

University of Pennsylvania, 3401-C Walnut Street, Suite 300, C Wing, Philadelphia, PA, 19104, United States

Jianjing Kuang

Popular version of 4aMU6 – Ultrasound tongue imaging of vowel spaces across pitches in singing
Presented at the 186 ASA Meeting
Read the abstract at https://doi.org/10.1121/10.0027410

–The research described in this Acoustics Lay Language Paper may not have yet been peer reviewed–

Singing isn’t just for the stage – everyone enjoys finding their voices in songs, regardless of whether they are performing in an auditorium or merely humming in the shower. Singing well is more than just hitting the right notes, it’s also about using your voice as an instrument effectively. One technique that professional opera singers master is to change how they pronounce their vowels based on the pitch they are singing. But why do singers change their vowels? Is it only to sound more beautiful, or is it necessary to hit these higher notes?

We explore this question by studying what non-professional singers do – if it is necessary to change the vowels to reach higher notes, then non-professional singers will also do the same at higher notes. The participants were asked to sing various English vowels across their pitch range, much like a vocal warm-up exercise. These vowels included [i] (like “beat”), [ɛ] (like “bet”), [æ] (like “bat”), [ɑ] (like “bot”), and [u] (like “boot”). Since vowels are made by different tongue gestures, we used ultrasound imaging to capture images of the participants’ tongue positions as they sang. This allowed us to see how the tongue moved across different pitches and vowels.

We found that participants who managed to sing more pitches did indeed adjust their tongue shapes when reaching high notes. Even when isolating the participants who said they have never sung in choir or acapella group contexts, the trend still stands. Those who are able to sing at higher pitches try to adjust their vowels at higher pitches. In contrast, participants who cannot sing a wide pitch range generally do not change their vowels based on pitch.

We then compared this to pilot data from an operatic soprano, who showed gradual adjustments in tongue positions across her whole pitch range, effectively neutralising the differences between vowels at her highest pitches. In other words, all the vowels at her highest pitches sounded very similar to each other.

Overall, these findings suggest that maybe changing our mouth shape and tongue position is necessary when singing high pitches. The way singers modify their vowels could be an essential part of achieving a well-balanced, efficient voice, especially for hitting high notes. By better understanding how vowels and pitch interact with each other, this research opens the door to further studies on how singers use their vocal instruments and what are the keys to effective voice production. Together, this research offers insights into not only our appreciation for the art of singing, but also into the complex mechanisms of human vocal production.

 

Video 1: Example of sung vowels at relatively lower pitches.
Video 2: Example of sung vowels at relatively higher pitches.