Wednesday, September 3, 2008

Liquid Focus or “Morbidezza”, a point of efficiency

The term morbide in Italian means literally soft to the touch. It is often used in singing to mean a tone that is not hard or muscularly tense. Recently I came up with the term “Liquid Focus” in helping a student experience the flexible efficiency of phonation. As important as empirical information is to singing, it means little if we do not have a way to communicate the implementation of such information.

As far as balance in phonation is concerned, the misunderstanding between the nature of falsetto and full voice is one of the most significant problems we have in vocal pedagogy. Little is possible without efficient phonation and achieving such a state is sometimes very time-consuming depending on what muscular balance or lack thereof exists in the given voice. Singers who sing with great flexibility and fluidity will state with strong conviction that full-voice feels like a continuation of what is referred to as falsetto or flute voice. Many others maintain that the increase of sub-glottal pressure that is necessary to full voice by definition means that full voice can never feel like falsetto. However efficiency as defined by scientists includes the concept of supra-glottal inertial air, discussed here before. SGIA confirms that in a resonant acoustic environment, the air above the vocal folds essentially acts as a facilitator increasing the length of the open phase and accelerating the close phase. In essence, the increased sub-glottal pressure is converted to air release increasing breath flow and therefore glottal amplitude considerably. In other words, the pressure that is built up during the short close phase is immediately released during the open phase. This exchange of pressure and release happens every fraction of a second. For A4 (440Hz, vibrations per second), this exchange occurs every 1/440 second. The resonant pressure-flow process results in a sensation of flexibility and softness that has been called morbidezza by the Italians.

The great problem with achieving liquid focus in our time is that the rushed nature of vocal pedagogy accepts the ability to sustain a pitch with enough carrying power to be a viable objective and that the ability to sing softly or flexibly is a special skill that some have by nature and others not. This kind of myth must be eliminated if vocal pedagogy is to recapture its original splendor. Teachers in Italy used to go to great pains and many years to achieve the kind of flexibility that results in the ability to sing for hours. This level of efficiency induces greater fluidity and viscosity and is consequently renders the singer’s work less tiring and more consistent. Stamina in singing is not so much an issue of strength in the large muscles of the body (although being well-toned is important to any activity) but rather to the balanced strength in the laryngeal musculature that makes the mechanics of liquid focus possible. To have the ability to sing like the great singers we must get our instruments balanced to the level that their instruments are. Those that begin with certain natural abilities have a difficult time believing that it should take disciplined and targeted work to get the instrument to behave efficiently.

Few singers exemplified this flexible, flowing, liquid tone as well as the great Catalan soprano, Montserrat Caballe. In the following clip of Signore Ascolta, she demonstrates the total control of her phonation by increasing her volume in the middle range at will, as at 1:10 on the word "labbra". Her approach to the top notes above the second passaggio is never aggressive even when forte. The final note demonstrates her amazing flexibility. The breath control for which she is so renowned would be impossible if her laryngeal mechanism were not perfectly balanced.





Her liquid tone is never compromised even at the softest volumes as in this breath-taken rendition of Strauss' Morgen.






On the men's side, there is the great Beniamino Gigli whose rendition of non ti scordar di me from the 1935 film that bears the same title. Gigli sings between pianissimo and mezzo piano, but it is clear that this is a voice that could crescendo to a big forte.

http://www.youtube.com/watch?v=8tk3Eb_zx4o


This ability to render a well-supported piano and better yet a messa di voce is very scarce indeed in our time especially among male voices. For that reason, I include here this excellent rendition of Lamento di Federico by the excellent Maltese tenor, Joseph Calleja.




© 09/03/2008

6 comments:

Martin Berggren said...

Thanks for another informative and helpful post! Liquid Focus sounds just right; something we all strive for!

TS wrote:
However efficiency as defined by scientists includes the concept of supra-glottal inertial air, discussed here before. SGIA confirms that in a resonant acoustic environment, the air above the vocal folds essentially acts as a facilitator increasing the length of the open phase and accelerating the close phase.

Here, I must add a question mark; where have you seen this? (I have not seen such a statement in the voice science literature I have browsed.)

TS wrote:
In other words, the pressure that is built up during the short close phase is immediately released during the open phase.

Well, are you sure about this? What is shown (I refer to the argument in Titze's 2008 article in JASA) is that supraglottal inertia (remember that inertia means "sluggishness" of a mass - here the supraglottal air mass - to respond to applied forces) delays the acceleration of air as the glottis is opens from a closed state. The reverse happens when the glottis starts closing from a fully open state, that is, inertia makes the air continue to flow. However, when the glottis closes completely, there is a cut off of air supply, so the air flow stops immediately. All of this means that even if the glottis is moving sinusoidally (that is, no harmonics in the movement), the air pulse will be skewed to the right, looking something like a saw tooth with a rich harmonic content. Now, what about the sound pressure? The pressure pulse will also be a saw tooth pulse, but there is a phase difference of half a period, which means that when the glottis opens, the pressure is rising and "half the way" between min and max.

The important conclusion here, in my opinion, is that the inertial load creates a rich harmonic spectrum, even if the glottis movement does not contain any harmonics. In practice, I think this means that also a very light phonation, where the vocal folds barely collides can also produce squillo through nonlinear effects caused by inertial load.

Toreadorssong's Vocal Technique Blog said...

Dear Martin,

Thanks again for keeping me honest. I was attempting to simplify the concept for those who are not that scientifically versed. Even for me (not a scientist) who spend hours trying to decipher some of those physics formulas, some of this escapes me. While it is clear to me why supra-glottal impedance maintains air pressure even during the open phase and thereby maintains glottal energy, I am not secure how the phase differential impacts this. More reading.

Relative to my statements above, the way I justify this is as follows: At the beginning of the open phase, supra-glottal impedance maintains a certain level of breath pressure close that of the sub-glottal pressure level just before the open phase. When the glottis begins to open, that pressure becomes intra-glottal thereby continuing to further the open phase. The pressure polarity changes from positive to negative when the glottis "begins" to close, still during the open phase. The negative pressure I believe accelerates the folds to closure. However before we get total closure, the pressure polarity changes again and the process begins again. In this sense, the folds never close too tightly. We get a sense of continuous release, that easy phonation I refer to as liquid focus.

I can imagine that my statement may be scientifically borderline inaccurate, but in essence, when the supra-glottal pressure is raised by occlusion (e.g. the [i], [u] vowels and consonants that close the lips)the glottal flow tends to increase. In essence, the close quotient is lower. The folds stay closed for a shorter period of time during each cycle.

I may be missing a crucial part of this and I am open to you setting me straight about this. This is a new concept for many of us who are not scientists by trade.

Martin Berggren said...

TS wrote:
While it is clear to me why supra-glottal impedance maintains air pressure even during the open phase and thereby maintains glottal energy, I am not secure how the phase differential impacts this.

A technical remark: acoustic impedance (or, to be precise, acoustic "reactance") comes in two flavors: it can be inertial and it can be compliant. Supraglottal inertia indeed maintains air pressure as the glottis opens, which helps open up the vocal folds if they are postured in a way that allows this (I believe this is an important point; the deep vocal fold occlusion associated with the raw chest voice is not so much affected by supraglottal reactance). Supraglottal compliance works the opposite way and tends to be destructive: that's the passagio problem!

Regarding the phase difference: acoustic volume flow and acoustic pressure always obey this "duality": when one has a maximum the other has a minimum; that's the half-period phase difference. For instance when the glottis opens and experiences inertial supraglottal load, the pressure is elevated and the volume flow is low.

TS wrote:
Relative to my statements above, the way I justify this is as follows: At the beginning of the open phase, supra-glottal impedance maintains a certain level of breath pressure close that of the sub-glottal pressure level just before the open phase. When the glottis begins to open, that pressure becomes intra-glottal thereby continuing to further the open phase. The pressure polarity changes from positive to negative when the glottis "begins" to close, still during the open phase. The negative pressure I believe accelerates the folds to closure.

The above is precisely in line with my understanding, although I have problems thinking about it in terms of pressure. I prefer to think about the volume flow: when the glottis opens, inertia causes the flow to start moving only after some time delay, but when the glottis closes, the volume flow immediately stops, since the source vanishes. Using the "duality" of volume flow and pressure, we get the picture you outline above.

TS wrote:
However before we get total closure, the pressure polarity changes again and the process begins again.

This other "jump" of pressure I am not so sure about...

Anyway, you seem to "advocate" a mode of phonation with quite a small closed quotient, is that right? However, I have just finished reading McCoy's "Your voice" and Miller's recent "Resonance in Singing" (thanks for pointing out the existence of the latter!) who both discuss closed quotients quite extensively. They seem to argue (there are some supporting sound examples) that a small closed quotient is associated with a female head voice and a male breathy falsetto, that is, sounds not so rich in harmonics. The conclusion to me seemed like a male "full" voice is associated with a quite large closed quotient. Are you running EGGs on yourself? Any comments?

Toreadorssong's Vocal Technique Blog said...

Thanks Martin for your response. This is becoming clearer all the time. I value your contribution greatly. I must make a trek to Northern Sweden soon to meet you.

I have run EGGs on myself using VoceVista. In fact the first time that I did an EGG was in 2005 when I sang a concert in Montreal. I met Donald Miller there and he did the EGG. He was moderately surprised by my high CQ in the upper range (around 80--very high). But he said that he found this kind of high CQ among robust voices in particular. He also said that my voice did not sound at all pressed. He heard me as a bass-baritone. Now since I am a tenor who was falsely singing dramatic baritone then, in retrospect I believe that I did press, but because I was not in my true high range, it did not sound so pressurized.

I have talked with Don Miller about the high CQ theory and that I believe that the observations in robust voices are due to preconceptions about how robust voices should sound as opposed to the natural balanced state of those instruments. I believe that a vocalis-dominant production in those voices make for a heavier production than necessary and a higher CQ than ideal. My own CQs now are not above 60 when I feel I am singing well, and the energy in the 2000-3500 Hz range is much stronger than ever. So I am convinced that high CQ is not necessary. Your countryman, Johann Sundberg believes in an ideal of 50/50 close/open quotients. I don't believe that ideal can be sustained but I believe that when we take supra-glottal inertia into account, we can get close to that idea. More lyrical voices tend to carry better in the theater because what is expected of them in terms of color is consistent with the products of "flow phonation". The dramatic voices can gain from this as well.

Martin Berggren said...

TS wrote:
I must make a trek to Northern Sweden soon to meet you.

Would be wonderful, you are so welcome! But be wary, I may threaten to visit you as well! I am traveling regularly and might be able to squeeze in a visit either to Berlin or NY...

About the CQ, it was highly interesting to read your comment; it really confirmed my suspicions! I could not completely buy the benefits-of-a-high-CQ-theory in McCoy's and Miller's books. It must be beneficial to utilize the resonance powers of an inertial tract, simply because it makes it possible to extract more sound energy from the breath! (There is another technical term for this: "impedance matching"). But a very chesty phonation (a mucosal wave originating deeply in the glottis) does not (at least according to Titze) interact much with the vocal tract, so a lighter approach is needed for a strong interaction. The fact that inertial loading makes phonation easier is apparently old news. However, that nonlinear effects of inertial loading can potentially create a full spectrum even without the vocal folds really colliding seems to be a very recent discovery!

Toreadorssong's Vocal Technique Blog said...

Sorry I did not reply earlier, Martin. I thought I had posted your comment, at least.

I had discussed the CQ subject with Miller. I had a hard time buying it because singers like Bjoerling, Gedda, Wunderlich, Dieskau and Gigli on the men's side and Caballe and Price especially on the female side. These singers had this amazing ability to maintain great vocal energy while singing very flexible and to my ears with little strain.

I think Miller was trying to be objective. He has studied the robust voices in particular. He played several samples of voices with high CQ levels that were able to perform a messa di voce. The conclusion was that if they had the ability to accomplish this very difficult task, that the production could not be wrong. I did not comment back then.

But now given my own experience with my robust voice, I would have to disagree. I believe that little significance is give to the strength of the CT-vocalis coordination. The ability of this balanced antagonism to handle pressure makes it possible for certain singers to accomplish this intricate muscular gymnastic without a break even when the acoustic nature of the vocal tract is not the most efficient. Nevertheless, the ideology should be for best efficiency. As I get closer to my goal, I experience a release in my sound that I think some famous tenors might have wanted. I need greater strength in the CT still to have the stamina necessary to sing in the heights for long periods of time. I know that I could not make it the way a singer like Domingo sings. To my ears he experiences great pressure, but apparently has the kind of strength I mention above.

NY or Berlin or Umea, we'll meet soon.