The Formant Formula – Why Low Voices Cut Through – Voice Science

Here's something that makes absolutely zero sense: You're out there giving it everything you've got—singing in a choir, a musical theater pit, an a cappella group, maybe even solo with a band behind you—and despite what feels like full volume, you're getting completely buried in the mix. The sopranos are cutting through effortlessly. The instruments are drowning you out. You push harder, your throat tightens, and somehow you're still disappearing. Meanwhile, you've heard other singers in your voice type—tenors, baritones, basses, altos—who seem to project with this brilliant, ringing clarity without any visible strain. How are they doing that?

Here's the answer: Trained male singers have a concentrated boost of acoustic energy in a specific frequency region—between 2,500 and 3,500 Hertz. This spectral peak, called the singer's formant, lives in a frequency region where the human ear is maximally sensitive. What this means is that whether you're competing with an orchestra, a band, background tracks, or other voices, you can get projection without force—not through pushing harder, but through acoustic strategy.

I'm Drew Williams-Orozco, and this is The Voice Science Podcast. In this episode, I'm going to explain exactly what formants are, why they matter for projection, and how male voices use a specific resonance strategy—the singer's formant—to cut through acoustic chaos without amplification or vocal strain. This is Part 1 of a five-episode series on formants. Today we're focusing on male voices. Next week, we'll tackle sopranos and mezzos—why high voices use completely different acoustic strategies. Then in Part 3, we'll dive into the alto voice and the hybrid approach that combines both strategies. In Parts 4 and 5, we'll explore how to actually teach this stuff in the studio.

Let's dive in.

WHAT ARE FORMANTS + THE SINGER'S FORMANT

Quick Formant Fundamentals

Before we can understand the singer's formant, we need to understand what formants are in the first place.

Here's the big picture: Your voice is a two-part system. Your vocal folds produce the sound—that's the source. Your vocal tract shapes the sound—that's the filter. This is called the source-filter model, developed by Swedish researcher Gunnar Fant in 1960, and it's the foundation of everything we know about vocal acoustics.

When your vocal folds vibrate, they create a complex tone that's rich in harmonics—the fundamental frequency plus a whole series of overtones. But here's where it gets interesting: Your vocal tract—the tube extending from your vocal folds to your lips—doesn't amplify all those harmonics equally. Instead, it has specific resonance frequencies where it naturally amplifies sound more strongly. These resonance frequencies are called formants.

We number them from lowest to highest: F1, F2, F3, F4, F5, and so on. For adult male voices, F1 typically ranges from about 250 to 900 Hertz depending on the vowel. F2 runs from 600 to 2,500 Hertz. F3 sits between 1,500 and 3,500 Hertz. F4 and F5 are even higher.

Why does this matter? Because formants selectively amplify certain harmonics of your voice while leaving others alone. When you align a harmonic with a formant—what we call formant tuning—you get maximum acoustic output and efficiency. Sometimes achieving this alignment requires vowel modification, which we'll discuss later. Your voice becomes louder and more resonant without requiring more effort from your vocal folds. That's the fundamental principle underlying everything we're going to discuss today.

The Singer's Formant Phenomenon

In the early 1970s, Swedish researcher Johan Sundberg began systematically investigating why trained singers could project over orchestras. What he discovered became one of the most important findings in voice science: trained male singers—tenors, baritones, basses—all exhibit a prominent spectral peak centered around 2,800 to 3,400 Hertz. This peak is about 1,000 Hertz wide, and it shows up regardless of which vowel you're singing. Sundberg called it "the singer's formant."

What this means is that your vocal tract can act like an acoustic amplifier—selectively boosting energy in a frequency region where you need it most. This isn't some mystical gift. It's learnable physics.

Here's what creates this acoustic phenomenon: The singer's formant results from a clustering of your third, fourth, and fifth vocal tract formants—F3, F4, and F5—all bunching together in the 3 kilohertz region. When these three formants converge, they create a single, powerful concentration of acoustic energy instead of three separate smaller peaks.

But why does this matter? Three reasons:

First, whether you're singing with an orchestra, a band, background tracks, or in a choir with other voices, the singer's formant occupies acoustic real estate where competing sounds tend to be quieter. Orchestral instruments, for example, have their strongest energy around 500 Hertz—right where your fundamental frequency lives when you're singing in your lower and middle range. The singer's formant lives in the 3 kHz region where the orchestra barely whispers. Rock bands, gospel groups, even dense choral textures—they all leave more acoustic space in this frequency region than in lower frequencies.

Second, the human ear is maximally sensitive around 3 kHz. Hearing sensitivity drops off both above and below this frequency. Why is the human ear so sensitive in this region? One leading hypothesis: evolutionary biology. Human infants' cries peak around 3-4 kHz, and some researchers theorize our auditory system may have evolved to be maximally responsive to those frequencies—which means the singer's formant exploits a built-in perceptual advantage! You're putting acoustic energy exactly where listeners' ears are most responsive—regardless of musical context.

Third, this spectral peak is strong. We're talking 20 to 30 decibels more energy in this region compared to untrained singers. Put another way: if you develop a strong singer's formant, you get a 20-30 dB boost in the frequency region where listeners' ears are most sensitive. That's the difference between being heard and being buried in the mix, whether you're in an opera house or a contemporary worship service!

Now, how do you actually create this? Sundberg's 1974 research identified the physiological mechanism: You need a widened pharynx combined with a narrowed epilarynx tube. If you're not familiar with the term epilarynx, it's the space enclosed by your vocal folds, your epiglottis, and your aryepiglottic folds—basically, the tube right above your vocal folds. When you widen the pharynx and narrow that epilaryngeal space, you create an additional resonator within your vocal tract that produces a formant right around 3,000 Hertz.

Later MRI studies by Matthias Echternach and colleagues actually visualized this in action—and watching professional tenors sing through the passaggio while lying in an MRI machine, not easy by the way, confirmed Sundberg's model. The research is still exploring the fine details of exactly how different voice types optimize this configuration, but the basic mechanism is clear: widen the pharynx, narrow the epilarynx.

Perceptually, this is what voice teachers call "ring," "squillo," "ping"—that bright, carrying quality you hear in trained singing. And here's the thing—this is related to what we talked about in Episode 4 on Ring and Twang, but the singer's formant is a specific acoustic clustering, not just general brightness.

Now, you might be thinking: "Is this just nasality?" No. One of the more interesting misconceptions is that brightness equals nasality. The singer's formant is pharyngeal and epilaryngeal resonance—it's not nasal resonance. When you're producing a strong singer's formant, your soft palate is actually raised, blocking off the nasal cavity. This is measurable physics created by learnable vocal tract adjustments, not some mystical property gifted to a chosen few.

Here's something crucial: Sopranos have the capacity to create this same F3-F5 clustering, but they can't use it effectively in their upper range. Why? When your fundamental frequency gets really high—as it does in the upper soprano range—the harmonics are spaced too far apart in the 3 kHz region to make this strategy viable. We'll explore this in detail next week, including how sopranos can and should develop the singer's formant in their lower range.

Altos face a related challenge: they need to use singer's formant strategies in their lower and middle range, then shift toward soprano-like formant tuning in their upper range. It's a hybrid approach. Even non-operatic tenors singing high contemporary repertoire may need to blend strategies in their upper range.

But for most of the low-voice range—tenors, baritones, basses, and altos in their lower and middle registers—the singer's formant is your primary projection mechanism.

THE PASSAGGIO – ACOUSTIC TRANSITION

Alright, now let's talk about what happens acoustically when you sing higher—and specifically, about navigating the transition zone classical pedagogy calls the passaggio.

Look, if you're fine with your voice quality changing as you ascend—if a lighter, more speech-like sound in your upper range works for your repertoire and aesthetic goals—you don't need to worry about what I'm about to explain. But if you want one consistent voice quality across your entire range, this acoustic shift matters a lot.

If you're a tenor or baritone, there's this pitch region—what classical pedagogy calls the secondo passaggio—usually somewhere around E4 to G4, roughly 330 to 392 Hertz—where your voice suddenly feels heavy. Stuck. Like you're muscling through every note. Your teacher tells you to "cover" or "let it turn over," but those instructions feel maddeningly vague. What does "cover" even mean?

Here's the acoustic explanation that makes everything click.

The problem in the passaggio boils down to a relationship between your fundamental frequency and your first formant.

In your lower and middle range, your fundamental frequency—F0—is well below your first formant frequency, F1. Let's say you're singing a C4—that's middle C at 262 Hertz. For an open vowel like /ɑ/, F1 might be around 700-800 Hertz, so multiple harmonics fall below F1—your fundamental at 262 Hz, the second harmonic at 524 Hz, the third harmonic at 786 Hz, even the fourth harmonic at around 1,050 Hz.

Now here's the key principle: formants don't amplify everything equally. Think of a formant like a spotlight—harmonics that land close to the formant's center frequency get a strong boost, and that amplification fades as you move away. In this /ɑ/ example, your third harmonic at 786 Hz is right near F1's center around 700-800 Hz, so it gets major amplification. Having multiple harmonics below F1 means you have more opportunities for close alignment—not just with F1, but with F2 and other formants too. The more harmonics you have in play, the better your chances of hitting those resonance peaks. This creates what acousticians call "open timbre," and it feels bright, full, easy.

Here's what's really interesting: Sing that same C4 on a closed vowel like /i/, and you get a completely different acoustic picture. F1 for /i/ is around 230-270 Hertz—much lower than /ɑ/. At C4, your fundamental at 262 Hz is very close to F1 around 250 Hz—that's excellent alignment, strong amplification there. But your second harmonic at 524 Hz? It's now far from both F1 and from F2, which for /i/ sits way up around 2200-2400 Hz. When you have fewer harmonics below a formant, you have fewer opportunities to land close to those resonance peaks. This is what acousticians call "close timbre" territory. Depending on your voice and technique, you might notice /i/ and /ɑ/ feel quite different at the same pitch—and now you know why: they present completely different acoustic relationships between your harmonics and formants.

But as you ascend in pitch, your fundamental frequency rises while your formant frequencies are essentially fixed for a given vowel—formants define the vowel itself. They only change when you modify the vowel by changing your vocal tract shape.

Eventually, F0 starts approaching F1. You might notice this happening somewhere around D4 or E4. In fact, at E4-G4, F0 can match or even exceed F1 for some vowels, which allows temporary F1:F0 tuning in this zone. And when that happens, acoustic conditions change dramatically.

Here's the critical shift: When your second harmonic, H2, rises above F1, the timbre "closes." Acousticians call this "close timbre," and pedagogically, this is what "covering" means. It's not a metaphor. It's a specific acoustic relationship where H2 has crossed above F1.

Without appropriate adjustments, trying to keep H2 below F1 as pitch continues to ascend forces you to progressively lower F1, which becomes increasingly difficult and inefficient. The voice feels heavy because you're fighting against the acoustic tendencies of the system. You're trying to maintain an "open timbre" relationship past the point where it's acoustically viable.

So what's the solution?

Here's the thing: you allow H2 to rise above F1 by making coordinated vocal tract adjustments. Specifically, you lengthen your vocal tract, which uniformly lowers all your formant frequencies. How do you lengthen your vocal tract? Two main strategies:

First, lip protrusion. Rounding your lips or slightly pursing them adds effective length to the vocal tract, lowering formants. Some teachers use the image of "fish lips and bunny teeth"—protruding the lips while keeping the teeth slightly apart—to access this vocal tract lengthening.

Second, slight laryngeal lowering. Allowing your larynx to descend a bit also adds length to the tube, lowering F1 and F2. Now, this laryngeal lowering is primarily a Western classical technique. If you're singing contemporary commercial music, you might raise the larynx instead—different aesthetic, different acoustic strategy. But the principle remains: adjust the vocal tract to manage the formant relationships.

These adjustments don't just solve an acoustic problem—they make singing easier. You're working with the physics, not against it. You create the acoustic space for H2 to rise above F1 without losing resonance or requiring excessive subglottal pressure.

Now, here's where the singer's formant comes back into the picture. While you're lowering F1 and F2 through vocal tract lengthening, you want to maintain that singer's formant cluster up around 3 kHz. You're creating a specific spectral envelope—the overall shape of acoustic energy across frequencies—darker in the lower formants, bright in the upper formants. This is the acoustic reality behind the traditional Italian concept of "chiaroscuro"—light and dark balanced together.

Practically, this comes down to tongue position. A higher, more forward tongue produces brighter sound and tends to raise the larynx. A lower, more retracted tongue darkens the sound and allows the larynx to settle lower. Your tongue is the steering wheel for these acoustic adjustments.

You're maintaining brightness through the singer's formant while allowing the lower formants to darken through vocal tract adjustments. That's what creates the covered sound—remember, that's when H2 rises above F1—while maintaining resonance through the singer's formant.

MRI studies by Echternach and colleagues published in 2014 actually captured this in real time. They had world-class tenors sing through the passaggio while lying in an MRI machine—not easy, by the way—and watched their vocal tracts adjust. The researchers documented increased jaw opening, lower laryngeal position, and varied pharyngeal configurations depending on the vowel context. These weren't arbitrary adjustments. They were systematic strategies for managing the acoustic transition.

Here's something else the research reveals: Different vowels present different acoustic challenges in the passaggio. A 2017 study by the same research team found that the vowel /a/—"ah"—is associated with greater phonatory stability through the transition region compared to higher vowels like /i/ or /u/. Why? The vowel /a/ has a higher F1 and lower F2 compared to vowels like /i/ or /u/, which means the acoustic relationships stay more favorable as you ascend through this pitch region. This provides acoustic justification for the common pedagogical practice of initially training passaggio negotiation on open vowels before extending the skill to more challenging vowel contexts.

Start with /a/. Get comfortable with the covering sensation on that vowel. Then gradually apply the same principles to /e/, /i/, /o/, /u/. This isn't just traditional wisdom—it's acoustically sound progression.

One more critical point: Anticipation.

The singers who navigate the passaggio most smoothly don't wait until they hit E4 or F4 to start adjusting. They begin making subtle vocal tract modifications well before the critical acoustic condition arrives. Maybe as early as C4 or D4, they're already starting to lengthen the vocal tract, already beginning the darkening process. And there's also a laryngeal adjustment happening: the thyroarytenoid muscles thin and stretch as you ascend, shifting the mechanical behavior of your vocal folds. This vocal tract work coordinates with that laryngeal shift, which is why anticipatory adjustment matters so much.

This creates gradual acoustic transitions rather than abrupt register shifts. It's the difference between a smooth, seamless ascent and a sudden break or flip. Preparation beats reaction every time.

PRACTICAL APPLICATION

Okay, you made it! Congratulations. That was a lot of acoustic physics. Now let's turn all of that into something you can actually use in your practice room today.

Developing Singer's Formant Awareness

The singer's formant shows up in classical singing, musical theater, gospel, some pop and rock styles—it's not exclusively operatic. If you want to develop this acoustic quality, you need to train two main components: pharyngeal space and epilaryngeal narrowing. The specific imagery you use will depend on your aesthetic goals and what your body responds to.

For pharyngeal space, you're looking for a sensation of internal width—like the beginning of a yawn, or the feeling of surprise. Some singers find it helpful to think of a sensation of lift or height in the soft palate area. Try this: on a comfortable pitch around C4 or D4, sing an /ɑ/ vowel ("ah") and feel that internal space open. Hold it for 3-5 seconds. You should feel width, not tension. Common mistake? Pushing the pharynx open with muscle force—that creates tension. Instead, allow the space.

For epilaryngeal narrowing, you want a slight sense of focus right at the level of the larynx. Here's an image that works: think of the teasing sound kids make—"na na na na boo boo." Try it on a pitch around G4 or A4. That forward, buzzy quality helps access the right kind of narrowing. Recent research suggests this narrowing is actually driven by root of tongue retraction, which narrows the aryepiglottic space without collapsing the pharynx. You should feel a slight constriction at the base of your tongue, not in your throat.

When you get both adjustments coordinated—widened pharynx plus narrowed epilarynx—you'll feel and hear the ring emerge. It's not subtle! There's a distinct increase in brightness and carrying power, even at moderate volumes.

SOVTEs—semi-occluded vocal tract exercises like lip trills and tongue trills—can help you explore these coordinations in a lower-pressure environment. Just remember: the goal is to transfer that coordination into open vowel singing, not rely on the semi-occlusion indefinitely.

Passaggio Work

For navigating the passaggio, remember: Start modifications before the critical pitch.

If your secondo passaggio hits around E4 or F4, begin practicing vocal tract lengthening adjustments at C4 or D4. Experiment with slight lip rounding. Allow a subtle laryngeal descent—not forced, just released. Notice how the timbre darkens.

Practice singing five-note scales: C4-D4-E4-F4-G4 and back down. On the vowel /a/. Focus on maintaining consistent tone quality through the entire scale by progressively increasing the vocal tract lengthening as you ascend. The top note should feel easier than the middle notes if you're making appropriate adjustments.

Now, here's the thing: I'd encourage you to explore both approaches—maintaining one consistent voice quality through vocal tract adjustments, and allowing a lighter, more speech-like register shift. Even if you primarily sing contemporary music where register breaks are totally acceptable, understanding how to smooth that transition gives you more options. And if you're a classical singer committed to one voice quality, knowing what happens when you don't make these adjustments deepens your understanding of the acoustic consequences. The more strategies you have in your toolkit, the more musical choices you can make.

And here's a pro tip: record yourself. You can't hear what you're actually doing while you're doing it. Listen back and notice the acoustic differences between the two approaches.

Then extend this to other vowels. Same five-note pattern, but now on /e/, /o/, /u/. Notice which vowels feel more challenging. Usually, /u/ is trickiest because its normal speech F1 is extremely low—around 300 Hz or even lower—and F2 is also low and close to F1. To maintain acoustic efficiency in the upper range, you need to raise both formants significantly, which essentially transforms /u/ toward /o/ or /ʊ/.

The practical technique here is vowel darkening or vowel modification. As you ascend, allow /i/ to shift slightly toward /e/ or /ɪ/. Allow /e/ to shift toward /ɛ/. Allow /u/ to open toward /o/ or /ʊ/. You're not distorting the vowel into something unrecognizable—you're making subtle adjustments that maintain acoustic efficiency while preserving intelligibility.

A Note on Alto Voices

If you're an alto, you use a hybrid strategy. In your lower and middle range, you develop the singer's formant just like male voices—widened pharynx, narrowed epilarynx, that characteristic ring around 3 kHz. But in your upper range—above about B4 or C5—you start incorporating some soprano-like strategies, particularly F1 to F0 tuning. We'll explore soprano formant strategies next week in Part 2, and then dive deep into the alto's unique hybrid approach in Part 3.

This hybrid approach creates the alto's characteristic timbre: darker and richer than soprano, brighter and more penetrating than mezzo in the same pitch range. You're blending acoustic strategies from both voice types, which is part of what makes the alto sound so distinctive.

The practical implication: Don't try to force soprano technique in your lower range, and don't try to force low-voice formant strategies in your upper range. Your voice has its own acoustic requirements that draw from both approaches.

CONCLUSION

Here's what you need to remember from all of this:

Formants are the resonant frequencies of your vocal tract that selectively amplify certain harmonics of your voice. For male voices—tenors, baritones, basses—and for altos, the singer's formant is your primary projection mechanism. It's a clustering of F3, F4, and F5 around 2,800 to 3,400 Hertz, created by widening your pharynx and narrowing your epilarynx.

In your lower and middle range, you use harmonic-to-formant tuning: aligning upper harmonics with formants to maximize resonance.

In the passaggio—that critical E4 to G4 region—you make a systematic acoustic shift. You allow your second harmonic to rise above your first formant by lengthening your vocal tract through lip rounding and slight laryngeal lowering. This is what "covering" means acoustically. And you maintain brightness through the singer's formant while allowing lower formants to darken. That's chiaroscuro.

Altos use both strategies: singer's formant in the lower range, and some soprano-like tuning in the upper range. We'll explore this hybrid approach in detail in Part 3 of this series.

Here's the empowering reframe I want you to take away from this episode:

The voice isn't a mystery requiring decades of trial and error. It's an acoustic instrument governed by physics. Opera singers 200 years ago didn't have spectrographic analysis or MRI studies, but they figured this out through sensation and sound. Now you have both: the traditional wisdom AND the scientific explanation.

When you understand the formant strategies your voice type needs, you stop fighting against your instrument and start working with it. That's what makes singing feel easier, sound better, and last longer.

Next week, we're tackling high voices. Why can't sopranos use the singer's formant strategy we just discussed? What do they do instead? Spoiler: It's completely different physics, and if you teach both voice types, you need to know both strategies. See you then.

This acoustic awareness—understanding HOW your resonance works, not just that it should "ring"—is exactly what we explore in VoSci Academy. We have Practice Paths specifically designed for developing formant awareness and singer's formant skills in male voices, with exercises that progress systematically from basic pharyngeal space work through advanced passaggio strategies. It's the kind of intentional, science-informed training that used to take years of trial and error.

Keep Singing Smart.

REFERENCES

Austin, Stephen F., and Ingo R. Titze. "The Effect of Subglottal Resonance Upon Vocal Fold Vibration." *Journal of Voice* 11, no. 4 (1997): 391-402.

Bozeman, Kenneth W. *Practical Vocal Acoustics: Pedagogic Applications for Teachers and Singers*. Hillsdale, NY: Pendragon Press, 2013.

Echternach, Matthias, Michael Burk, Fabian Burdumy, Marie Köberlein, and Bernhard Richter. "Vocal Tract Configurations in Tenors' Passaggio in Different Vowel Conditions—A Real-Time Magnetic Resonance Imaging Study." *Journal of Voice* 28, no. 3 (2014): 262-267.

Echternach, Matthias, Michael Burk, Louisa Traser, Marie Köberlein, and Bernhard Richter. "The Influence of Vowels on Vocal Fold Dynamics in the Tenor's Passaggio." *Journal of Voice* 31, no. 4 (2017): 423-429.

Fant, Gunnar. *Acoustic Theory of Speech Production*. The Hague: Mouton, 1960.

Henrich, Nathalie, John Smith, and Joe Wolfe. "Vocal Tract Resonances in Singing: Strategies Used by Sopranos, Altos, Tenors, and Baritones." *Journal of the Acoustical Society of America* 129, no. 2 (2011): 1024-1035.

Miller, Donald G., and Harm K. Schutte. "Formant Tuning in a Professional Baritone." *Journal of Voice* 4, no. 3 (1990): 231-237.

Miller, Donald G., and Harm K. Schutte. "Toward a Definition of Male ‘Head' Register, Passaggio, and ‘Cover' in Western Operatic Singing." *Folia Phoniatrica et Logopaedica* 46 (1994): 157-170.

Miller, Richard. *Training Tenor Voices*. New York: Oxford University Press, 1993.

Nix, John. "Vowel Modification Revisited." *Journal of Singing* 60, no. 3 (2004): 291-296.

Sundberg, Johan. "Articulatory Interpretation of the ‘Singing Formant.'" *Journal of the Acoustical Society of America* 55, no. 4 (1974): 838-844.

Sundberg, Johan. *The Science of the Singing Voice*. DeKalb: Northern Illinois University Press, 1987.

Sundberg, Johan. "Level and Center Frequency of the Singer's Formant." *Journal of Voice* 15, no. 2 (2001): 176-186.

Titze, Ingo R. *Principles of Voice Production*. Second printing. Iowa City: National Center for Voice and Speech, 2000.

Titze, Ingo R., and Brad H. Story. "Acoustic Interactions of the Voice Source with the Lower Vocal Tract." *Journal of the Acoustical Society of America* 101, no. 4 (1997): 2234-2243.

Titze, Ingo R., and Johan Sundberg. "Vocal Intensity in Speakers and Singers." *Journal of the Acoustical Society of America* 91, no. 5 (1992): 2936-2946.