So, how does one go about tuning the 3rd, 4th, and 5th formants? It is my understanding from reading Sundberg, Titze, and a lot of other stuff, that the fourth and fifth formant are essentially fixed by nature and can only really be affected substantially by lowering or raising the larynx, which lowers or raises all formants. The third if I remember correctly depends on the tip of the tongue...
From what I have observed in my students lighter voices tend to have higher F4 and F5 and lower voices lower ones. I, for instance, seem to have F5, even with a completely depressed larynx, no lower than about 3300.
Perhaps the especially ringy voices are simply gifts of nature, and not "tuned" in the same way F1 and F2 can be "tuned." This would also explain why different singers have certain notes that just ring better than everything else--like Lauri-Volpi's Bb.
Our friend Klaus asks the very question that occupies all our minds. I am in Umeå, Sweden at present and just finished having a very significant chat with my friend and sometimes student, Martin Berggren, an acoustic scientist, with a beautiful voice (Swedes are blessed in so many ways vocally).
First let us count out the idea that some people have "ring"and some do not! I have spent the last 72 hours with Swedish singers and I am more convinced than ever they have advantages due to their language, their default speech frequency, their country-wide choral tradition and overall love for music as an indispensable part of life. It is no wonder they hold a significant number of operatic jobs around the world. The Swedes and the "ringing" Italians have a lot in common in terms of speech. The common Swede (particularly male) speaks with a very high resonance that resembles nasality but is not completely. It is the same brilliance that many United States Country singers have as a result of the Southern/South-Western accent. In all these cases, the sound may indeed be accompanied by some nasality because there is a tendency toward a high larynx when Italians, Swedes and U.S. Americans with a South-Western accent speak (high larynx and a lowered soft-palate usually occur together). Yet the brilliance of the sound is not due to the nasality but rather to narrowing/lengthening of the epi-laryngeal tube.
Now to the point! First the third formant: At a conference in Stockholm last fall, one of the presenters was an overtone singer, who demonstrated with spectrographic display how he can control the third formant at will. I asked him personally how he was able to so effectively effect the 3rd formant and he responded that it was based on the movements of the "tip of the tongue" (as Klaus suggests). He completely charmed the audience that day and I found his control quite spectacular.
As for the fourth and fifth formants, I believe we can manipulate them as well. The overtone singer did specify that he believed (as do scientists) that the fourth and fifth formant could be effected by adjustments in the aeryepiglottic fold (collar of the larynx or epi-larynx) and the depth of the larynx.
The way my acoustician-host, Martin explained it (he can correct me if I am wrong) is that the epi-larynx has a frequency of approximately c. 2800 Hz. The strength of that frequency is stronger when the epi-larynx is long and narrow and the surrounding pharyngeal space is expanded (low larynx). At its peak strength, the resonance of the epilarynx would draw the energy of the upper part of the spectrum to itself. In this way, it would raise the fourth formant and lower the fifth and have a powerful effect on the nearest harmonic.
It is significant that the Oblique Inter-Arytenoid that can bring the vocal folds together are the same muscles that could narrow the epilarynx. Lowering the larynx would also lengthen the epilarynx. Unlike the Lateral Inter-Aritenoids that also bring the vocal folds closer to each other but can cause pressing, it would seem the Obliques can do the same without inducing a pressed tone. The Western twang developed by Country Music singers could be attributed to this action, what I sometimes refer to as a focused head-tone (for lack of a scientific term). Incidentally, Swedes speak with the same twang. (I would mention that country singers generally do not show strength in the SF region because their production also depends on a high laryngeal position. Not the case with Swedes when they speak. They have the twang but with some depth in the sound as well. I have only occasionally come across a Swede who speaks only with the twang without a low larynx).
A twang that does not cause pressed voice allows the possibility of relaxing the pharynx (open throat) to effect the 1:6 ratio between the volume of the epi-larynx to that of the pharynx.
Achieving the narrowing of the epi-larynx is not as complex as it might seem. I believe it is a matter of experiencing this resonance and then deciding to utilize it. Producing an [i] vowel while the larynx is low (I have recommended the [hwi] exercise in a recent post) is a good mechanical way to achieve the lengthening of the epilarynx and the widening of the pharynx needed for the critical 1:6, 1:7...ratio that produces a strong singer's formant. This is a start. The adjustment of the [i] vowel can indeed be kept when singing other vowels, which is why teachers recommend exercises that lead into [a] from [i].
Very good results can be achieved with a relatively pressed tone. Even some of the greatest singers in the history of recorded opera sang with a pressed tone. Their charisma more than made up for the relatively venial sin of over-compression. Some singers have very strong extrinsic laryngeal musculature and can handle more sub-glottal pressure than the average. The fact that they can function successfully with this excessive pressure does not mean that it is the best way, nor that everyone can sing successfully with such pressure.
Indeed there are variations in what voice teachers will accept as a good source tone and much of that has to do with personal taste. For my part I will take, on the male side, the one singer who is practically without reproach both on the traditional and science side of the vocal discourse. And that is Jussi Björling.
Björling si m_ama.mp3
(Incidentally, when I feel I am singing really well, I have a feeling that there is a sensation of vibrant air directly on top of where I sense the folds vibrate. I cannot be sure this is impedance caused by supra-glottal inertia. It is possible that my knowledge of this makes me interpret the sensation in such a way. We must be careful with sensory feedback. Since that area of the larynx is not enervated it is important to keep a level of skepticism relative to interpreting proprioception).
I have tried to recreate the balance that Björling had by concentrating on the narrowing experience of the [i] while maintaining the depth of the [u]. This is the purpose of the [hwi] exercises. The results were spotty. Sometimes good, sometimes not. I was able to observe fault in my own singing in two ways: 1) As a former baritone, I am very conscious of removing unnecessary darkness in my tone. The lower voice was manufactured to created my old bass-baritone sounds (I sang a lot of Oratorio). However, I believe I took this idea too far and may have allowed my larynx to climb up slightly in pursuit of my new tenor sound. 2) A lot of the brilliance that gives the voice is "tenor" quality has more to do with efficiency of the source tone, meaning how well the folds stay in contact with each other to prevent breathiness and loss of necessary sub-glottal pressure. I may have been pressing a little bit to achieve this, which would have caused the slightly raised larynx to feel comfortable.
After having achieved a relatively good balance relative to fold posture (vertical depth of the folds), I felt comfortable working with the "occlusive" [z] to bring the folds together without pressing. Singing on a clear [z] (imitating a bee's buzzing) requires excellent fold contact without pressing. Maintaining this posture on the following vowel is the trick. If there is a little explosion of air going from [z] to the vowel, then it is a sign that the folds have popped apart. This exercise is also completely doable with the deeper laryngeal position. A good sequence would be [zi ze za] on simple up-and-down 5-note-scale: zi-zi-ze-ze-za--za-za-za-za. After working on this for a couple of days, I found that a difficult Purcell song, We Sing To Him, that I have programmed for an upcoming concert became considerably easier. My low range had been the more difficult part to deal with. Achieving good closure without pressing in that range made the approach to the treacherous Ab so much more organic. When I analyzed various parts of that clip, I was very happy to see that I was able to approach the balance that Björling exhibited on his Abs. The spectrum is dominated by the 3rd harmonic (H3) on the lower side and 7th (H7) on the upper side--That to say the clustering of F4 and F5 around the 7th harmonic. Otherwise, the energy would be split between two of the three higher formants F3, F4, F5. This balanced chiaroscuro effectively increase energy throughout the spectrum, so even the harmonics that do not carry most of the energy maintain a relatively high intensity. I compare this to an earlier Ab that I sang and the results are obvious.
20110829JRL m_ama si m_ama.mp3
I also learned from this experience not to dictate a vocal color for myself. I give this advice all the time, but sometimes I am not aware I am doing it. As one student said to me: "I have never heard a color like yours in a tenor!" That is both scary and reassuring. Heldentenors are fewer today not because there aren't any but rather because most of them are trained as baritones. Indeed traditionally, the heldentenors had very baritonal aspects to their sounds. Some more than others. From Vinay and Melchior to the tenors who sing the heavier Verdi and Wagner today, there is a very large distance. Indeed it was two types of tenors who sang Lohengrin and Erik on the one hand and Sigmund and Tristan on the other. A difference was made in Kloiber between the Jugendliche Heldentenor and the unqualified Heldentenor. Lohengrin and Parsifal is listed for both (I think the latter is a mistake in Kloiber. Character-wise, the young sound makes sense, but the tessitura of Parsifal is too low to be sung comfortably by a lirico-spinto/Jugendliche Heldentenor. I saw Götterdämmerung the other day and the Siegfried, Stephen Gould had a naturally darker timbre than the baritone singing Gunther. The fact is that the naturally darker timbre of the voice must not be sacrificed when seeking brilliance and vice-versa. If one can display a spectrum that shows such strength in both sides of the spectrum as displayed by Björling (and sporadically by me--I am getting closer), then one must accept the nature of the sound for what it is. The biggest trap is to limit our own voices to sound like someone else, even our most revered heroes. It is one thing to follow Björling's acoustic strategy and it is another to copy his sound. What should be heard in the best moments of my clip is balance relative to my own voice, which makes it unique unto itself, sounding nothing like Björling.