Friday, October 21, 2011

Kashu-do (歌手道): On Vibrato, A Point of Pedagogy: 2. Bleats and Wobbles

In the last post, I dealt mainly with the nature of vibrato (that it is inherent in the voice) as opposed to the nurture theory (that a vibrato is made, not inherent to the voice).  In this post I would like to address unbalanced vibrato. The two common qualitative issues relative to vibrato are bleats and wobbles, mistakenly referred to as fast and slow vibratos respectively.

It is important to know that a vibrato is defined not only by its rate, the number of oscillations per second, but also by its extent, the pitch range it covers.  The vibrato rate does not change from one moment to the next or from one day to the next unless there are issues to the efficiency of nerve function or dysfunction, which can be influenced by the effects of old age. But not necessarily!  Indeed vibrato rate (speed) is hardly the issue at all.

The problems we tend to identify as a slow or fast vibrato have to do with the pitch range that the vibrato covers or the vibrato extent.  Scientists have gauged an acceptable vibrato (one that does not distract the listener's attention) to have a pitch range of about a semitone or less.  Vibratos have been measured far in excess of a semitone (100 Cents: In acoustical measurements of vibrato extent, one Cent is defined as 1% of a semitone) among professional singers.  What is particularly interesting is that a singer's vibrato extent may vary greatly between one note in their range and another.  Extents may vary prominently between different registers as well.  All of it depends on the individual singer and this is the question that occupied my mind until a couple of years ago when I began to consider different modes of singing one pitch, relative to the dynamic activity in the antagonistic relationship between the Cricothiroyd muscles that stretch the vocal folds and the Vocalis that resists the stretch and causes tautness in the vocal folds (Scientists have shown that tautness of the folds make for more efficient pitch making than simply fold lengthening).

In my opinion, good singing begins with efficient pitch-making.  One pitch can be sung in different ways on a continuum of antagonistic activity between the two main muscle groups.  Given that pitch is basically based on the timing of one vibration cycle, there are many variations on how a pitch can be sung.  The length of the cycle depends on the vertical depth of the folds on the one hand (since the vibration pattern or mucosal wave occurs on the vertical axis of the folds) and the firmness or looseness of the closure between the folds.  A given cycle length (pitch, in simple language) can be produced either with folds that are vertically very thin and firmly pressed, vertically very deep and loosely closed or somewhere in between.  The correct in between is what we seek.  I believe that wobbles and bleats occur when the production is at the extremes.  Thick and loose production tend to cause flatness.  A singer with a good ear will always seek to compensate and so the mechanism will try to inch its way to balance between cycles.  This means that one moment the tone may be flat and the next in tune.  This variation registers in our ears as a slow vibrato when in fact the vibrato rate (how many vibrato cycles per second) has not changed at all.  The average pitch range of the vibrato relative to the frequency of the desired pitch is low.  Likewise, a pitch that is produced thin and pressed would hang on the higher side of the desired pitch and continually try to adjust to the desired pitch.  The average range of the vibrato would be higher but there would always be a move toward the center of the pitch.  The vibrato extent in both cases is actually wide, but the pitch range, sharp or flat, makes us perceive the vibrato as fast or slow respectively.

A thick or thin production can both be pressed.  A thick production that lacks good breath support would begin to squeeze and the pitch would lower audibly.  Such a singer over a long period of time, especially with older age when the breath mechanism can become lethargic, could end up with what sounds like a slow vibrato even if vibrato rate does not change (vibrato rate can change with older age).  Likewise a singer who sings thin and lacks adequate breath coordination could end up with an instability that sounds like a bleat, goat-trill or the Italian term caprino.  Such instabilities can occur at any point in life, but are more common in older singers, whose breathing function may become weaker due to lower physical activity and atrophy.  Singers who on the other hand have a balanced phonation (neither thin nor thick) tend to not exhibit a wobble even in advanced age.  A balance phonation is generally accompanied by excellent breath coordination, which maintains good muscular fitness as the singer ages.

One thing is certain, wobbles and bleats develop over time from phonation habits, which may not even have to do with principles of singing but rather the singer's normal speaking habits.  Poor speaking habits can undo good singing practice such that the singer never develops a since of security and consistency. 

© 10/21/2011

Tuesday, October 18, 2011

Kashu-do (歌手道): On Vibrato, A Point of Pedagogy: 1. Normal Vibrato and Preceived Straight-Tone

I don't think I have written a post before about vibrato because I thought the facts about vibrato have been discussed so much over the internet and voice forums that there was nothing pertinent to write about.  That is, until I found myself in the middle of a discussion in a forum of voice teachers, and I must say I was mortified, not so much by the probability that some teachers have not been exposed to the scientific facts about vibrato but by the absolute resistance of some to consider the scientific information because it contradicts a paradigm that has been sold as a method, for which books, etc have been produced.  This brings a really important point of pedagogy to bear, namely "Packaged Pedagogy" in favor of sensible debates based on the facts.

For this reason, as I am deep in the middle of writing a book that deals in great part with vocal technique, I am trying painstakingly not to offer this book as a The Method but rather as one approach based as much as possible on facts that we know and in certain cases based on analytical extrapolations based on what we do know.

Since I teach CCM (Contemporary Commercial Music) singers as well as opera singers and have done so for as long as I have been teaching, I certainly recognize that there are modes of singing that hold other values more important than absolute acoustic and muscular efficiency.  However differences in style and artistic aims do not decry the facts that scientists have dedicated so much of their time trying to pass on information to us that are central to our work.  As much as I think that the scientists could do a lot more to help disseminate the information they gather to the voice teachers in ways that are more user-friendly, I think the community of voice teachers is even more lethargic in doing its part to meet the scientists halfway.  I do not believe there is a discipline whereby so-called experts hold on to false information as much as we voice teachers do.

There are those who believe that the least the student knows about the workings of the voice the better, that way they are less likely to interfere with its workings.  Some truly believe this and it is not as ridiculously condescending as it may appear at first.  Singers are tinkers.  They like to "mess with the instrument" in an attempt to control it.  Smart teachers of all traditions understand that the workings of the voice are fairly automatic and that vocal training is more about getting the instrument in shape to do what it was designed to do without much help from us.

HOWEVER,  I do not seize to experience the amazement in students' faces when they get simple information that makes sense.  We do not need to give an anatomy lecture to educate the student about what they are responsible for in the process of singing and what happens automatically.  Understanding how the voice basically functions make for a confident singer not a complicated one.  If the student really understands the process (i.e. what is automatic and what needs their attention) they are less likely to tinker in a manipulative sense, but rather practice to find balance between their responsibilities and the automatic workings of the instrument.

Which brings me to the main topic, vibrato!  I will try to be as simple as I can be with this, but I will also try to be thorough:

1.  Muscular function relative to pitch occurs thus:

  • The singer desires to sing a specific pitch, the brain sends the signal via the two laryngeal nerves (superior laryngeal nerve and recurrent laryngeal nerve) to contract the many muscles of the larynx to create the desired pitch (and quality, as the singer imagines).  How well the singer's imagination turns into reality depends on how these muscles have been trained (consciously or unconsciously) over time.
  • The nerve impulses from the brain are intermittent. They occur between 5 and 7 times every second depending on the specific person.  The impulses are a reminder of the desired muscular function.  In between them, the muscles relax.  The vibrato is essentially a sequence of A-B-A: A) contraction of muscles to create desired pitch (and quality) B) relaxation of muscles and the pitch drops A) correction of pitch by new nerve impulse.
  • It is important to note that the crico-thyroid muscle, which stretches the vocal folds to make them thinner (it works in tandem with the internal thyro-arytenoid muscle [vocalis] which resists the stretch and keeps the folds taut.  The vocalis prevents uncontrolled thinning of the folds), is enervated separately by the external branch of the superior laryngeal nerve.  The CT is the central pitch-making muscle.  
2.  Vibrato in the fundamental sense is not a choice.  What is explained above occurs in every voice barring some kind of nerve damage.

3. Perceived vibrato vs. straight tone:
  • Straight tone is part of a continuum relative to the normal vibrant nature of the voice.  In other words, a voice functioning with muscular balance will be vibrant.  The vibrato pattern is not heard in speech because one specific pitch is not sustained long enough for the ear to perceive the regularity of the nerve impulses.  When a tone is sustained, with continuous, consistent breath pressure, the folds go into the regular pattern that bring out the regularity of the A-B-A pattern explained above.  However, if the breath pressure is inconsistent, or there is a great imbalance between subglottal pressure and transglottal flow, then the regularity of the pattern might be compromised and the vibrato not perceived.  This we judge to be a relatively straighter tone.  The vibrato pattern is still perfectly observable in spectrum analysis, but irregularity causes the ear to perceive it as non-vibrant. 
4. Proper vocal balance reveals the vibrato pattern. The vibrato already exists!
  • This is an important distinction to make.  A vibrato is not learned.  It manifests when the voice is functioning in a consistent manner relative to breath pressure/flow.  Thus when a singer achieves good vocal habits, the vibrato is simply revealed.
  • When a teacher teaches a student good vocal skills and the vibrato manifests, s/he might say: "I just taught the student how to make a vibrato"!  But this would be incorrect.  The truth is that the teacher taught the student the coordination that reveals the vibrato pattern in a regular manner to the listener's ear.  
5. Skilled singers can alter the regularity of the vibrato pattern to create a perception of straight tone:
  • Vibrato in the voice confirms learned skills.  So in a sense one could superficially say that a vibrato is learned.  But this has the effect of separating vibrato from the skills that reveal its innate existence.  
  • A vibrant voice in singing reveals that the voice has achieved relative balance.  From that healthy state, a skilled singer can alter the perception of vibrato to create many effects.  A skilled singer can alter the vibrato at will.  Classical music expects the voice to function in its natural vibrant, balanced state. Perceived straight tone in the classical tradition is an effect used for special circumstances. In non-classical traditions, the voice is expected to be in a vibrato-less state that imitates the less regular patterns of every day speech.  Vibrato is then perceived as an added effect instead of the fact that perceived vibrato is the hallmark of a balanced voice in singing.
6. Early Music and Straight Tone: The traditions of straight tone singing in Early Music traditions 
  • It is important to distinguish the importance of reducing the natural vibrato of the voice in acoustic circumstances whereby the natural vibrato would cause musical problems.  The motets of Giovanni Gabrieli, for instance, were written for the Basilica di San Marco di Venezia.  The echo effect of singing in cathedral of any size makes the voice's natural vibrato excessively problematic.
  • Choruses that included children's voices (boy's voices for the most part), as was the case in the renaissance and in the Catholic Baroque (including the Anglican tradition) would require modifications relative to their voices.  Children are perfectly capable of accomplishing a perceived vibrato, however it is more rare because the respiratory training that maintains consistent breath pressure at will is not normally developed in young children.  The adult voices of such choirs would have to make concessions both in terms of power and the perception of the vibrato if the chorus is to have a homogenized sound.  
  • The operas of the baroque period and the works of Bach would have no such restrictions.  The adult voices (Bach's choir , especially the castrati would have developed such amazing breath control as to make vibrato a normality, not an anomaly.  It is important to note that because a straight tone requires an inferior coordination relative to efficiency, music that requires great virtuosity such as the fioratura passages and long lines required in such works as the solo madrigals of Monteverdi and the solo works of Bach, Vivaldi and Handel, would necessitate the kind of efficiency of a vibrant voice.  A voice producing a perceivable straight tone also alters the resonance of the voice causing it to be less powerful relative to balance with an orchestra, even of modest size.  Modern performance practice, having establish a preference for straight-tone globally for Early Music, would seek solutions for orchestra balance that would make the natural inferiority of straight-tone singing viable.  It is also important to note that an inspired musician singing early music in straight-tone can be extremely convincing.  That also does not decry the natural inefficiency of perceived straight-tone singing.  It is important to add here that conductors might decide in a Draconian manner to eliminate vibrato when poorly train singers exhibit bleats and wobbles (next post).
  • We cannot currently go back in time to verify what the practices might have been. But it is unlikely from a scientific point of view that any music requiring extreme virtuosity would logically inspire straight-tone singing.
  • It is also important to realize that the voice is the only instrument that produces an inherent, "natural" vibrato.  Other instruments produce an induced, or forced vibrato, mostly attempting to imitate the nature of the voice.  It is conceivable that some composers dealing with children's voices and the vibrato-less nature of instruments might require their adult singers to suppress the natural vibrancy of the voice.  All of that is speculation and subject to musical tastes.  Researchers with a preference for straight-tone can make a good argument why one should approach certain works with a perception of straight-tone.  A good case can also be made for vibrato as being functionally necessary for extremely virtuosic vocal music.  The main point however is that vibrato is an inherent part of the human voice that is revealed (not imposed) through balancing the instrument toward its most efficient state for acoustic singing without artificial amplification.
The next edition will deal with unbalanced vibratos (i.e. wobbles and bleats).
© 10/18/2011

Sunday, October 16, 2011

Kashu-do (歌手道): Who can fix it?

In 1986, I had the honor, among all the male members of the Westminster Choir, to participate in a concert version of Rigoletto with Renato Bruson and Cecilia Gasdia conducted by then Music Director of the Philadelphia Orchestra, Riccardo Muti.  This was the beginning for me of many experiences with this magnificent conductor who not only made great music but inspired the young members of the Choir every chance he got.  During my time in the Westminster Choirs, I must have participated in at least two productions yearly with the Philadelphia Orchestra and took part in two recordings: Beethoven's 9th Symphony and Berlioz' Romeo et Juliette with Jessye Norman, Simon Estes and John Aler and James Morris among the soloists for the two works.

On one occasion when we were preparing Bruckner's Te Deum, Maestro Muti visited the campus as he always did for the first round of rehearsals.  In the Salvum fac populum, which includes a tenor solo, Maestro Muti began singing the solo in a very clear, pretty (if a little unsupported) voice.  It looks as if he was going to sing the whole solo, but when he got to the tenor high A, he took it one octave lower, and the Choir burst into laughter, because it looked like, up to the last minute, he was going to go for the A.  He, laughing, jokingly reprimanded us for laughing at him.  We were clearly laughing with him.  At our rehearsal the next day in Philadelphia at the Academy of Music, where we performed, the soloists were present.  Frank Lopardo was the tenor and I vividly remember Mark S. Doss as bass soloist.  When we got to the Salvum fac populum, Mr. Lopardo ripped into the solo, but when he got the high A, he turned to the chorus and took it an octave down, to which the normally very concentrated Westminster Choir under Joseph Flummerfelt, lost it and burst into a roar of spontaneous laughter.  You see, Maestro Muti explained that for our benefit, he called Mr. Lopardo in the night, who was traveling from Milano and prepared the joke with him.  Some 25 years later, I am here retelling the story on this blog.  I have a great love for this man, and was very happy that he is the recipient of the Nilsson Prize.  Furthermore, it is my great hope that Maestro Muti will be around for a long time and as this tenor voice of mine is taking shape, I put the dream out in the Universe that I might sing with him one day.  But my dream is not the subject of this blog!

Who is going to save our art?  How many times do we complain about how the art form is degrading by superficiality, etc?  And how many times the young singers who want to connect to the upper echelons of the business claim that everything is fine and that we middle-aged and older fogies are nostalgically remembering the past to the detriment of the future?

Recently the great violinist and conductor, Gidon Kremer wrote his now legendary letter of withdrawal to the Verbier festival administration, explaining his need to be true to himself and music by withdrawing from the superficiality of the music business for the sake of the art. There were as many letters from conductors and other musicians in support of Maestro Kremer's letter as there were business types who thought the letter was unfair.  But that this letter made its way through the Web so quickly speaks to its resonance throughout the music world.  Yet there is no movement to reverse this on a large scale.  Does this mean that the world of music is not run by the artists, but by the business people? By the money?  Rhetorical question!  The bookkeeper is running the arts and that is the problem!

It is easy to talk about the problem, but what do we do about it?  My students often ask me about this.  To me, it is quite simple.  We start with ourselves! 

For my part, I teach a principle that requires a little bit of time in the case of singers who come with muscular imbalances.  But I put the hours in to make sure it does not take any more time than it needs to, but the student must be committed to the time that it should take.  Too many are not interested in a solid technique, but a quick fix.  I'm uninterested in those frankly and I usually know them when I meet them.  So I teach them as long as they can stand it, hoping they will leave with principles that might help them if they ever realize that there are no shortcuts.

For my part, I do not charge students more than they can afford.  I charge professionals more than aspiring professionals and work out a price with my students while teaching them as often as they need to be taught to really make a difference.  Yet it takes a lot of my time and as my studio grows I have to find ways to make it work more efficiently, but the quality of the teaching must not be compromised.

For my part, I keep challenging myself as an artist, till aspiring in my new tenor incarnation to be the best artist that I can be.  At 45 years old I should be skeptical of ever singing at a high professional level again, but I will be sharing my exploits with you soon.  I begin with a fund raising concert in Washington D.C. on 29 October 2011 to raise money to rebuild a music school that was destroyed in the Haitian Earthquake in early 2010.  Then I will participate in a reading of Mozart's Idomeneo.  Sounds humble? Yes!  But little steps lead to bigger steps.  I am not afraid of time!

And that is the problem in general.  As a teacher, I encounter a lot of singers who are afraid of the passing of time, while aspiring to master an art form that is supposed to be timeless.  The irony is disarming! 

But on the positive side, I work with a studio full of singers who are willing to take the time to do it right.  And it pleases my heart so very much that I discovered the Muti clip this morning while I had my morning coffee at Starbucks in Berlin, near my studio, after traveling on the night train from Bonn, having heard one of the singers I guide in a thrilling performance of the title role of Puccini's Manon Lescaut.  More important, I drove her from Zwickau to Bonn on Sunday because she needed to rest after her triumph the night before as Tosca in her home theater.  Her Manon sounded totally fresh, after that full-out Tosca the night before.  That is old school!  As long as there are musicians like this excellent soprano, who embodies patience, we will not have lost it all. 

But for the art of music to conserve its dignity, it will be up to all of us to have the guts to take the time to do it right and believe that at the end of the day, substance trumps a nice hairdo and a six-pack any day!  If you don't believe it, become a pop singer! Nothing wrong with it!  Just don't be a pop diva posing as a classical musician!  The two are and should be two different things that share certain elements.  For the record, I am a proud owner of a six-pack, but I am not going to present myself to La Scala tomorrow because of it.  If it serves me in addition to a fully developed musical talent, so much the better, but I would never want to go to my grave wondering if I only got to sing because of it!

Every sign is pointing to the end of the superficial excesses in our culture during the past generation.  I firmly believe that the values that made singers like Birgit Nilsson will dominate again.  I recommend we all join the reconstruction!

© 10/16/2011

Saturday, October 8, 2011

Kashu-do (歌手道): The Singer's Formant and the Singer's Formant Region 2: How to achieve the ring

The following comment by our frequent contributor, Klaus Georg is worth its own post:

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].

The [i] vowel has the wonderful property of having its 3rd formant coincide with the Singer’s Formant frequency (c. 2800).  As said, the mechanics of the [i] vowel correspond with the lengthening/narrowing of the epi-larynx, by virtue of the paradoxical stretch upward from the displacement of the back of the tongue (hyo-glossus muscle) and downward if the larynx maintains its depth. This is achieved very well by the [hwi] exercises.  We have gotten awesome results with this exercise in the studio.

Indeed some vocal tracts are naturally suited to achieving the 1:6 ratio that produces the singer's formant.  A singer with a very wide or deep pharynx will naturally have an easier time with respect to producing "ring",  it does not mean it cannot be learned.  Perhaps there are people with very small pharyngeal volume that would have a real hard time producing the ring in the voice. So far I have not had a student who could not eventually accomplish the coordination.  Given that nature created the laryngeal structure precisely for long distance communication without artificial amplification (Please let Opera remain this way--This was one of Salvatore Licitra's plea by video that was shown at the award ceremony in Ragusa, Sicily shortly after his fatal accident), it is a rare human being who cannot produce this sound.  Babies need it to alert their parents of discomfort or danger.  The propagation of the species necessitated this before technological advancements of the Industrial Revolution.  Agrarian and otherwise non-urban cultures make use of the Singer's Formant for communication, such as calling the animals home at the end of the day.  An example of this is the Swedish tradition of Kulning.

It is interesting that Birgit Nilsson, who prided herself on being a farm girl, practiced this traditional animal call.  There are many traditional songs that came out of Kulning. (I had a coloratura student use her experiencing with Kulning to access more intensity in the middle range.  I had wished to include that recording here, but we found out after the lesson that the recording machine was not on.  It was quite extraordinary and I am very sad we were not able to record it. But I do have a recording of her from the day before singing some extremely high notes.  Look for it in the next post!)

The other part of this is the source tone.  We cannot talk about the effects of the singer’s formant on the upper part of the spectrum without a good source tone.  The folds must be deep enough to create a tone rich in harmonics and must come together completely and gently for efficient propagation of air. Closure alone is not enough. A low larynx is part and parcel.  A “natural” low larynx is achieved in part when there is a pressure/flow balance.  Too much medial pressure will create excessive sub-glottal pressure and force the larynx up. One difference between a pressed tone and a good closure without excessive medial pressure is the contact area.  As said here so often, if the contact time is increased by medial pressure, the vertical contact area must reduce to maintain pitch, since both add time to the length of the glottal cycle.  Conversely, increased contact area requires a relaxation of medial pressure if pitch is constant.  This is theory, but in my experience it makes complete sense.    

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 had a relatively lyric voice (as opposed to a dramatic voice).  By this I mean a naturally lighter voice.  The vocal folds were not as substantial as that of Corelli’s or Del Monaco or even Pavarotti.  One can extrapolate this by ear.  The latter three produced sounds that were simply more substantial as far as source tone. To my ears however, within the limits of his own natural voice, Björling sang as substantial a tone as was possible and still maintain balance.  On that score, he produced a more substantial tone relative to his own instrument than Pavarotti.  This substance helped produce the kind of source tone that was also amenable to a larynx that floats low.  He did not have to use external forces like depressing the larynx with the back of his tongue.  The tongue was free to configure as necessary for proper acoustic adjustments.  Furthermore, he had such a sensitivity to the Singer’s Formant’s effect that he used it constantly.  The balance between the low part of the spectrum and the upper part of the spectrum is faultless in Björling. Here is pretty much a map to what a tenor wants to achieve in terms of chiaroscuro balance.

Björling si m_ama.mp3

Also significant is the influence of the Singer's Formant on the source tone itself.  Martin Berggren suggests that because the epi-larynx is directly above the vocal folds, it would make sense that the propagation of acoustic energy between the epi-larynx and the pharynx would produce an impedance to the glottal flow, in essence keeping the glottis closed for a brief moment during each cycle even as the folds begin to open. This has the virtue of reducing the length of the close quotient without losing efficiency or compression.  It sounds like the glottis is not closed tightly and yet the voice produces amazing brilliance and ring.  Sounds like Björling at his best to me!

(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.

Earlier clip:

20110829JRL m_ama si m_ama.mp3

Later clip:

20110924JRL We sing to him_rehearse.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.