What is a Vowel Formant?

Something I have been thinking about throughout this semester is the idea of formants.  I wondered why we were all instructed to use and think about the same ones. Why is it true that we would all have the same formants despite having different voices and ranges?
We often hear people’s ranges talked about as though they are unique to how high or low they can sing. For example we might say “my chest voice is from this note to this note, my mix is from this note to this note, and my head voice is from this note to this note” and we would base that off of some sort of unique quality of our voice. After some discussion with professor Bentley as well as some deep thought and reflection I began to evolve the way I think about range. The idea of formants is not about the range itself necessarily, but rather, specific adjustments that everyone can make to achieve resonance, not only depending on the note, but also the vowel shape and tongue placement.
Has anyone else been thinking about similar things? Let me know!

This adjustment in paradigm is truly slippery. If you guys feel able to discuss it at all amongst yourselves, I think you’d find that conversation really helpful– even if only to settle on specific questions regarding confusing points. One big hurdle, ironically enough, is just the word “formant,” which sounds like ‘I shape something with my body’– which is close, but not exactly what it refers to. Formants are bandwidths in the spectrum of sound waves that are more highly resonant—in fact, they are sometimes referred to as ‘the First Resonance… the Second Resonance…’. Sounds with formants at various frequencies are perceived as various vowels. So, though we adapt the shape of our Vocal Tract to boost these various bandwidths, what we’re doing is creating an instrument that plays a vowel– and the vowel, by its nature, has certain distinct formants.

This tricky distinction goes to the heart of your observation, “Why do we have the same formants despite having different voices and ranges?” The nature of a vowel determines its formants (…and vice versa). By making a certain vowel, and matching each others’ versions of that vowel, we are building shapes that boost the formants of that vowel, rather than boosting the formants of some other vowel. Singing a scale on a given vowel entails hearing and feeling how our voice sweeps past formants as we change pitch. The ‘fundamental frequency of oscillation,’ aka the first harmonic, aka the note you’re singing, interacts with formants– but also, higher harmonics (H2, an octave above H1; H3, a 12th above H1; H4, two octaves above H1) will interact with a formant. Each time a harmonic sweeps past a formant, we lose its boosted contribution to the timbre, the color of your voice– and that is as it should be, if we want to continue with resonance. Resonance continues; timbre evolves. Hang in there! You’re all doing really, really well with this info.

I have been focusing on “rebuilding my vocal walls” like we talked about in our lesson, and it’s helped a lot with resonance and making sure I’m not straining my voice or being nasally. I have a few questions about brakes and formants though. I’m still not exactly sure what that means still and how to apply it.

Lordy, I bet you would hear the same thing from almost any one of your studio mates! Little by little. I think you worked well today, and you’re right, I could hear the improvements you built in in your practicing right away! I’ll wrap up for now by just humming that same tune:
there’s a shape, and a breath management, that allows each vowel on a given frequency (note) to be its most efficient, with resonance that accumulates and reinforces the stability of that shape and appoggio (breath management). If you’re feeling strain, and/or hearing a strained timbre, including issues having to do with intonation and smooth, resonant diction– then something’s amiss. The shape and the appoggio are not working in tandem, and are therefore not the best resonance strategies for that vowel on that pitch. Making moves between pitches, or between phonemes (the building blocks of your text), or between timbres (expressive colors)– and any and all combinations of those three variables!– asks us to find the move that keeps us on the resonant path through that transition.’

While in my lesson last Friday I noticed that as you get lower on the vowel dial, the vowels have a higher formant. For example, /u/ and /i/ have a format on Eb4 where as an /a/ has a much higher formant. I was wondering if there was a correlation between position on vowel dial and the formant. Thank you!

Absolutely, 100%. Make sure you’re looking at the cause, though– my snazzy purple chart isn’t the cause. It’s just a quick thing to point to, to externalize the proportions inside your resonator. As the tongue height and shape varies, like a tall table with a small surface, or a lower table with a larger surface, the ratio of contribution from a vowel’s first formant and second formant vary. We focus on the first formant (f1), because its impact on timbre and sensation is more readily perceived, since its frequency is lower. There’s also a second formant (f2), a second boosted bandwidth, higher up the spectrum. Those two boosted bandwidths together are the “fingerprint” that we name with a vowel (/a/,  /e/, etc). We call them “the vowel formants.” There are other formants, higher up, but it’s the first two that define the identity of one vowel vs another.

/i/ and /u/ have a very similar f1; the contour of your pharynx, the vocal tract up to the height of the tongue, is very similar. /i/ has a very high f2; /u/ has a much lower f2; the contour of the vocal tract downstream of the tongue height– the over-vowel– varies. /e/ and /o/ have a similar f1; the contour of your pharynx, the vocal tract up to the height of the tongue, is very similar. /e/ has a much higher f2 than /o/ does; the contour of the vocal tract downstream of the tongue height– the over-vowel– varies. /a/ (as you point out) has a much higher f1 — and its f2 comes up sooner than the f2 of other vowels. 
SO! Those unique ratios mean that some vowels (/i/, /u/) are recognized because of a ratio that favors space upstream (behind; inside of you) of the tongue-height. Your tongue is heaped up high; your pharynx is relatively open. The /i/ has a smaller chamber at the front of your resonator than does the /u/; its f2 bandwidth is higher. An /i/ sounds bright and distinct over more of your range, thanks to so many harmonics still benefitting from that extra-high f2. But we recognize both /i/ and /u/ by that high haystack of a tongue. /e/ and /o/ have a not-so-low f1; they have a middle-high table, with the tongue a bit more even throughout your resonator. The /a/, with its high f1, is the most evenly distributed tongue shape. its f1 and f2 are close to each other. A double boost for your notes below F#5; not much boost past that.

Whew, right?!? But, yes. Our vowel dial models a variety of tongue heights / shapes. Those shapes mean that certain bandwidths will boost the resonance of all harmonics below them– and the frequencies which are boosted vary, as the tongue shape varies. We name those various colors “vowels.”

[Adding in breath management: ideally, the tongue is simply tuning resonance. If, however, we fail to recruit other options for breath management, it jumps in, stiffening, flattening, to muffle resonance, and slow your breath.]

Obviously, I’m happy to unpack this stuff. It’s not my invention. It’s the way resonance works. But (also obviously), people have sung beautifully for centuries, relying on an appetite for the sensation of best-resonance to guide their technical choices. If/when you are teachers yourselves, someday, you could opt out of insisting your students grasp any of this. One need not understand any of the acoustic rationale. But I believe it makes my teaching consistent, and efficient (and frustrating, and frustrating, and frustrating). I have a Dream that the full explanations will allow you to take over at the wheel, sooner.

Getting oriented to basic (but new!) technical instruction

It’s crazy that the semester is almost over! I remember being so lost during my first few lessons because I didn’t know anything about resonance. I know now there is so much to learn, but I’m becoming more interested in how everything works because I’m just a curious person. At first, I was overwhelmed by all the new information and got a little frustrated when I didn’t pick it up that quickly. Now, I’m starting to understand more about how the voice works and how to fix things when I don’t sound good.
One thing that still confuses me is consonants. I can’t really figure out when words should connect and when breath should stop. I’m actually excited to learn new pieces and explore more over the break while I don’t have as many other things to worry about.

I’d offer that breath is always cued up and leaning, ready to move. If you’re on a plosive (i.e., “stopped” consonant, like k, b, t, etc.), then it’s paused at the shape of that consonant, like a bookmark, so that you can pick up exactly where you left off. And we roll to a stop against resistant resonance for a rest, for offset.
Otherwise, sound continues. An important bit of info re consonants is that they are very useful once we’ve navigated higher than f1 [the first formant], as a way to identify “the ground floor,” the slightly higher level of the larynx. Divergence-back is a move beginning from that re-defined ground floor.
You’re doing great. It’s super confusing! If you feel like the mists are beginning to clear, after only one semester, you are officially doing great!

Is anyone else feeling a bit emotional this week? I certainly am. Having our last studio class and my last lesson has made me a little wobbly. Not knowing if those were lasts or just lasts for the semester is very difficult for me.

Anyway – a thought I wanted to share about offsets. Up until studying with Julia, my plan for offsets (or cutting off, stopping the sound, however you want to word it!) was basically just to cross my fingers and hope it wasn’t bad. Something Julia said in my lesson this week really clicked for me and I am probably going to poorly paraphrase it: “change your shape to that of a higher note.” Like I said, it’s probably a terrible paraphrasing, but I translated that into simple-speak as: pretend you’re going to sing a higher note after the last note of the phrase, but don’t sing it. 

And it WORKS! I feel my inside shape changing to the shape of a higher pitch and the offset is clean and clear and smooth. No more finger crossing! (Well, some, I don’t always get it right, but you get the point).

Going back to being emotional and sentimental – thank you all for making my first (and maybe last?) year in the Bentley studio amazing. You all welcomed me in with open arms and it has been such a joy to sing for you and get feedback from you, and to hear you all sing and grow. You are all such wonderfully talented and kind people, and I love you all <3

I cannot improve on any of your words, VD. 
Well… ok, just to earn my paycheck: you move to the undervowel of a higher note. It’s an important distinction, since the committed overvowel is intact all the way into silence. You can feel your tone “roll to a stop.”
But otherwise: I’m totally in agreement. I’d be a happy camper to just have y’all keep showing up (after a week of good practice, of course) indefinitely.

Sometimes, when I discuss my major, people will respond by saying things like, “You should try to teach me to sing.” It is interesting how singing, being one of the most musical, natural sensations a person can feel, is still so sorted into the idea of can vs. cannot, especially within the music world. When seriously thinking about how to pedagogically approach the idea of singing, the first thing I’d want to stress to singers, young singers in particular, is how singing is a strategic, purposeful act not an act of tension or strain. The concept of ‘supported’ singing is certainly one that can promote unhealthy tension in a young singer, and I’m definitely still working on issues of tension in my own singing. I think implementing ideas of resonance strategies, and exploring how the voice naturally fluctuates without artificial manipulation, is good in working with a beginning vocalist.

I’m fond of making the punny distinction between singing with intention, rather than singing within tension. The crazy thing about the sensation of strain is that it’s a red flag that you’ve strayed off the resonant path (either breath management or resonator shape is out of whack)– though so often a singer interprets it as their failure to be strong enough to get farther in this strained direction– pretty much “if it’s difficult, it must be right.” Training heightens the nuanced coordination of breath and shape– our improved singing is a result of that fine range of motion, not a result of bench-pressing more weight.
I’m pleased to hear you say you’d reach for resonance strategies for a young, beginning singer. I’d like to believe that an aversion to evidence-based learning, for fear of overwhelming a younger singer with scary scientific stuff, is just a miscalculation. Young singers are ready to learn… often more readily than old teachers! The next time someone says “you should teach me”… you should!

Physical and Vocal expressivity

I struggle so much with the performance aspect of solo singing, which doesn’t make a lot of sense because I’ve spent most of my life doing musical theatre and having no issue expressing myself in that setting.  

Where should I start?  I notice a lot of opera singers tilting their upper bodies and doing this kind of swiveling thing… I obviously don’t know how to describe it.  I think the easiest way to start implementing expression in my performance is to start with my face, but that also feels very difficult now because I’m thinking so much about resonance, which involves my mouth and takes away that fraction of facial expression.

It’s a valid concern. And your observation on the swiveling singers is also germane. Whatever you see, while watching a singer (unless they’re truly, truly in character) is the body at work on the voice. What feels like they’re giving themselves over to expression is literally… ex-press-ion– i.e., they are twisting and creating resistance, and pressing their breath delivery out (“ex”) against that little torque. So, how can we be visibly expressive without playing our voices like a set of bagpipes? How can you love your long resonator without looking like a carp all the time? 

Easiest to set aside is concern about the expressive body. As soon as we can distinguish between moves that are actually ersatz vocal technique, and moves that are expressively potent, there’s nothing preventing you from doing as much of the latter as you like. Facial expression is more demanding. There’s no getting around the fact that the shape of your resonator affects the color and functioning of your voice. First directive again is to activate your expressive body. Second is to make huge use of moments of inhalation to exercise the facial muscles, give us a smile, take your acting moment– then build to sing. Your viewers are aware that you are singing. Putting your expressive, nuanced voice out there is going to move them. Don’t confuse making faces with pouring out colorful, emotion-decked sounds. You don’t want to look downright mournful when you’re singing about the thawing spring brooklets– but your singing voice is a huge expressive asset (when you’re using it super-expressively), and can supplant facial gesture to a miraculously large degree.

This week as I’m still working on the physical expressiveness, I find a very interesting thing. I always feel a little awkward to sing with body movements, to add some performance in my singing. However, I do lots of acting when I’m teaching children and I feel much more confident when I’m teaching. I think it is because I have many chances to teach kids and I’ve already established my own teaching style. However, I don’t have many chances to sing on stage as a solo, which makes me feel embarrassed sometime because it’s just not what I often do. I don’t believe in what I’m acting, and that makes me distracted because I have to think about some “fake” movements when I’m singing. Fantastic performers, please give me some suggestions on how to be myself when I want to perform a piece.

Ironically, I think a very helpful mind-set for physical animation is exactly that: I imagine I’m telling this info, at the speed of the actual musical phrasing, to a crowd of second-graders assembled for story hour. As I touched on in studio, the real make-it-or-break-it moments are the transitions between phrases. What might you do to keep those kids’ attention from wandering away? It need be no more than signaling “Well, wait till you hear this next bit!” I get the “feeling fake”– but it’s only fake if you don’t truly want to keep our attention. A majority of our moments are spent paying attention to others– so, crafting a span of time with the intent of staying at the center of your listeners’ attention feels atypical— but not inherently artificial. Deciding on moves and dramatic beats is like studying best pedagogical practices: just because you’ve learned how to achieve your objective, and you then put that skill into action, does not mean you’re a fake teacher!

This week in conducting we discussed vocal production from childhood through late adulthood. Henry Leck presented on the adolescent boy’s changing voice and showed an example of a Japanese boy’s choir that utilized a lot of movement. The boys actively rocked back and forth while doing a lot of movement with their arms. The director claimed that this helped the boys achieve more full, artistic phrases. I wish I had the video because it was super interesting. I’ve never seen a group sing Ubi Caritas while moving so freely. How do you all feel about active physical movement in choral music? Does it distract you too much or do you think it is okay to achieve the sound one desires?

I’d say this sounds like the perfect situation to blow their little boy minds open with some uninhibited motion! I’d hope you’re all aware, from your own work as well as from observing each other in class, that we are prone to defensively stiffening, and not freely expanding for a new breath– as well as being reluctant to adapt fluidly for our varying vocal line (which consonants, which vowels, which frequencies, which timbres). And you’re also aware that for your solo work, with a ringing, resonant classical timbre, that we work on our skills to adapt fluidly within ourselves (literally). For me, in the context of my teaching, free, fun physical gesture is important to integrate– but only if the transfer is then made to internal coordination– rather than leaving the student with the impression that singing is only free and fun when we get to dance.


I noticed this week that memorizing “Nina” changed the quality of my performance drastically.  The obvious reason is that memorization got my face out of the stand and helped me to be my tallest self.  However, I feel like there is another, maybe equally as responsible reason for the change, and I think it’s confidence.  I know I still have miles to go in this area, but just that little extra bit of assurance really helped me this week.  I’ve never felt like a solo performer, but at least being able to emote the tiniest bit while I was singing (instead of reading notes off of a page) did something for my sound.  At least that’s what I think. I could have sounded exactly the same and been fooling myself!

No way. Memorization is so huge– because it’s a plan. Memorization means you know how to tailor your breath profile from onset; it means you’re moving along the most efficient resonant path— in the same sense that building for your initial phoneme cues up the best balance of shape and air management. Instead of putting out fires every step of the way, you’re using your vivid, artistic imagination! And when you add meaning into the mix, then you have built-in timbre, too. It’s so frustratingly ironic for a teacher, when students reserve memorization (let alone translation!) for the last step, the week before performance, when we know you’d need only a fraction of the technical tweaking you’re about to slog through, given the benefit of asap memorization. If it feels more artistically integrated to think about prioritizing emoting– Great! I like to think I can actually guide a singer through any and all physical adjustments. But really– it’s the instrument you were all designed to use. Someone can be a terrific voice teacher doing nothing other than lighting your creative fire to get a piece internalized. Go, KH!

I guess I’ve been a little stumped, but in a good way. I started working on Les Berceaux last week as I mentioned in my last comment. I’ve been exclusively practicing this piece for a little over a week now, and I feel so stumped because I’m not sure what to do next with this song. Obviously it isn’t perfect because that doesn’t exist, but I’m not sure if I know how I can improve this piece at the moment. I’m writing this outside of Professor Bentley’s room waiting for my lesson, so I’m sure I will have 100 things to work on in an hour and I can just delete this post! 
But I guess the question stands on what my fellow studio mates do to keep working on songs that are already at that “acceptable” level. 

Now we all want to hear if there was any more stuff worth integrating! 

I was just thinking about this, actually– what the pace is for moving through rep you’re studying, and whether you’re expecting me to declare a piece finished. Specifically, I was thinking about those singers now preparing aria audition videos, that have specific due-dates– so, they simply must be declared finished, at the date when they must be submitted. But my question to myself was, how do I best let these singers know that there’s always a further step to take, especially with arias and other rep that will (we hope) get you work– even after some particular submission has been made? There’s much we can explore in the realm of physical presentation, nuances of attitude and intention– but those layers cannot begin to be accessed until a piece is mastered– technically, internalized/memorized, fluently prepared with a pianist– and I’m certainly not going to say “sorry, you cannot submit this, because there’s more I have to say first!” Or “We will learn no further repertoire until this aria is 100% flawless.” And– I don’t get a chance to go further with anyone until this checklist is in place:

  • Is it correctly learned

  • Is every detail of the text intricately woven amid many layers of meaning?

  • Have the singer and pianist arrived at a seamless, nuanced understanding of each others’ parts, and musical goals?

  • Is it solidly memorized?

Generally, when a student can say Yes to all of those, we are at jury day, or performance day, or we really need to address some other repertoire. But in truth– this is just the starting point. From here on, I don’t want to be at the piano; I don’t want to be correcting diction, or resonance strategies, or discussing how your entrance springs from the piano writing, or explaining why we had decided to breathe here, not there– or pointing out that an inhale needs to be substantial! NOW I want to talk about expressive color, about facial expressions, about body language and gesture, about pacing, about a range of possible tempo choices, a range of motivations– You know I love resonance strategies. But make no mistake: nailing those is not the end, but the beginning of what we can explore in your lessons.

Aside from that, though: Some songs are easier to master than others (thank goodness). And part of your immersion in the rep for this degree is to make your learning skills stronger and stronger, with each assignment. If a particular assignment is feeling demoralizing, because it just. won’t. get. learned!– please remember that struggling with this one will pay off in ever-fewer future struggles, with each successive piece from now on.

I’m still at the very beginning of my vocal journey, but I don’t think a piece should ever be seen as done, dusted, and put on the shelf– if that’s a good expression. After you can check off the criteria Professor Bentley wrote above for a well-learned piece, sometimes you get into that rut when you wonder “what else is there to do to make this piece better?” I’ve sung Deh vieni non tardar SO many times that I could sing it in my sleep, but I know for sure that I haven’t explored all the ways I can master that aria even more. It may be much later when that happens, though, maybe a few years down the road when I find myself in the role of Susanna. I think you can never run out of ways to better a piece where you resonate more with the audience, yourself, the text and the notes on the page. That’s why being a musician is never boring. Sometimes when a piece seems exhausted or I know it by heart, I re-assess my character’s point of view. I’ve already sung Schubert’s “An die Nachtigall” as young girl watching her lover peacefully sleep, but what would it be like if I sang it as a mother singing her child to sleep? I think it’s also cool to see productions of the same opera but with different conductors or at a different opera company– it goes to show that even if you get into that rut, there’s always another way to give your piece a new spark, or even a completely different take and interpretation. So I guess what to do when you get into T’s current situation– I, as a young and inexperienced singer, try to be adventurous and explore all the possibilities of what I can do with that piece– vocally, musically, and as the character. And then, of course, I’d run it by Professor Bentley to see if I’m not getting too crazy. Does this seem like a good method, Professor Bentley? Any other methods to think about?

This is such a great take! I think it’s an excellent idea to explore new musicalities and new expressive tools to capture a different color or mood that can maybe alter the story or even just keep it interesting for both the audience and the singer getting tired of the same old same old! Thank you for this great comment!

I second that! I think weighing “do I bring this piece back in, though it seems to be functioning quite well?” vs “I’d better bring the next piece, and start de-bugging stuck consonants” is a difficult choice to feel confident of. Maybe urgency moves us both on to the de-bugging tasks, to the next tune on our lists– but if that means a voice lesson never ventures beyond de-bugging– well, that’s not very fun. I’d be sad to think you consider our time together to have a specific and limited scope. But I’d be intrigued to think of a lesson as a potential throw-down: “OK, Prof, I dare you to find something new to try with this!”

I do see in all of you, week after week, that technical work is bearing fruit. I certainly hope that the toolbox we’re assembling will look familiar and handy sometime soon, enough to then congratulate yourself on de-bugging your own tunes without me. I can’t quite get comfortable stepping away from a piece when I can hear there are still struggles we can fix. But then? I’ll put my feet up, and say “once more, but this time, sing it like you hate nightingales…” 🙂


A strange question popped into my head as I was practicing earlier. I was thinking about how you can start singing a song in a key other than the notated one and sometimes it actually feels more comfortable. I know it’s very common for pop singers to change keys to fit their voices better. Then I wondered whether it’s a valid choice to change the key of a classical song to make it easier, or if you should reach a point where you are so good at navigating the transitions of your voice that you can sing any piece in the original key? Just to clarify, I am referring to moving the key up or down by a step, not having different keys for different voice parts.

You’re right, this is an excellent question. There’s a tradition in opera, especially earlier opera, that a superstar singer would specify “I do this in F.” And clearly, our song repertoire is often available in multiple keys. A few things to consider: composers known for their vocal writing know what they’re doing, They are aware of what a voice tends to do around C4; around F5. There may well be specific timbral gestures a composer imagines and wants, which won’t happen in the same way if the piece slides up a step or two. Remember that these acoustic events we learn about do not change, voice to voice. Vowel formants are where they are.  If a song is performed by a man, an octave lower than by a woman, the quality of the high G (G4 for him; G5 for her) will be notably different. 

Your question focuses more on “oh, this feels MUCH better!” I’d say any art song (not aria) can indeed be transposed to suit a particular singer’s aesthetic and happiness. And a song has a lot of expressivity and potency, even if the registers don’t fall exactly where the composer imagined them. But. If you have the understanding of resonant vocal technique (as I believe you do), you also have the tools to make the excellent choices within the key at hand.

In working with young women, teachers often reach for a higher key. The student is lifted away from some registration issues; more vowels are working in a similar shape. The student is almost tricked into finding pillow air, an appoggio leaned entirely on resonance. That’s helpful! But it doesn’t help them understand tessitura below C5– or below G4.

In working with young men, we can step away from living in the challenging passaggio area (C4-F4) by deciding to stick with middle-baritone repertoire. We can get away with an occasional high note relying on crossed fingers and a bit of strain. But that doesn’t help them understand what happens around E3 on /i/– or around G3 on /a/.

That’s still not your question, though– you’ve got a song in one key, and it’s working pretty well. You find it a half-step higher, and it feels MUCH MUCH better. Ok. Part of that improvement is simply feeling excited by faster air. Part of it may be a certain sustained note that is happier for a woman’s octave than for a man’s. You get to choose your key. It’s still the same song. A voice used to functioning in a lower tessitura finds the key a whole step lower to feel “more like them.” They’re right; also because they’re happier with a little more color, a higher number of notes well below the f1. Maybe they’re not very good at handling the rib-air appoggio. They get to choose their key; it’s still the same song. But. Maybe the bumped-up key means the listener won’t get to enjoy a bit more color. Maybe the bumped-down key means the listener won’t get to feel wonder and elation at the sound of a voice ringing past a spoken tessitura.

Choral vs. Solo choices

Something I’ve been interested in for a long time is the treatment of resonance in a choral setting versus a solo setting.  Choir is my “thing,” so I’ve spent much more time implementing bits of advice from choral directors that don’t always necessarily contribute to my solo performances.

For example, I was always taught in choir to strive for the very darkest, richest sound.  This disregards a lot of the ping-i-ness that is so beautiful in solo voice.  If I’m thinking about it correctly, I feel that my choral directors always wanted the sound that I achieved by singing pretty much everything divergent back.

So are choral resonance strategies a world away from solo resonance strategies, or are they supposed to be the same and they’re just being expressed differently by directors versus private teachers?

Terrific question, and deductive reasoning, K. In solo singing, for projection, for balanced tone, and for a range of artistic timbre-use, we do indeed want access to more pinginess– that’s tuning the shape of your resonator to enhance the higher harmonics. And it involves being able to call on resonance strategies, like divergence, and also tongue shape, that give you that access. What are you not doing as soloist? Well– you’re not blending with 60 other random voices. You’ll notice that what it takes to achieve blend alters with the demographics of your ensemble, too– a middle-school choral conductor has a very different set of challenges than the faculty choral conductor at a music conservatory. In order to blend in USingers, you’ll need access to the brighter range of vocal color, too. I think you’re right, that guidance for young singers moves them towards a divergent-back shape, since all they use all day, every day, is divergent-front (in speaking– or hollering). But also, and harder to move away from in more advanced solo training: they are cued to flatten and stiffen their tongues. This improves blend (by reducing ringing harmonics), and also manages breath, thanks to not-best-resonance. We’d rather have the ringing harmonics, and free breath that is managed by resonance (and thanks to resonance, a stable, open thorax). I just got a nice new book on resonance and choral instruction– maybe you’d like to borrow it.