Monday, August 23, 2010

Kashu-do (歌手道): Science update: PAS5

During my time teaching in Stockholm, I was able to attend some of the presentations at the PAS5 (Physiology and Acoustics of Singing, 5th Edition) Conference.  I am hoping that our frequent blog commentator, Martin Berggren will contribute to this edition since he was also in Stockholm for the conference and attended all the sessions.

We were all elated by the presentation of Wolfgang Saus, a German overtone singer who demonstrated how to have direct control of the vowel formants. He demonstrated precise control of the third vowel formant, a remarkable skill. He uses formant tuning to reinforce specific overtones, with which he could fashion a melody. The third formant has long been associated with the area around the tip of the tongue and the frenulum linguae.  Nevertheless, to have such precise control of  this resonance band is remarkable. If anything, Mr. Saus showed us that we classical singers are only scratching the surface of resonance control. It was exciting to see the possibilities of the instrument from the point of view of an overtone specialist.  Mr. Saus presented a workshop, which I was not able to attend due to teaching commitments.  I hope to meet him in Berlin when he comes there.

Alberto ter Doest presented a workshop on accessing the singers formant, using a very twangy production. The process included using the extreme twang in a simple melody and then singing normally while attempting to maintain the twangy quality, associated with the narrowing of the aryepiglottic fold.  The strategy follows recent scientific confirmation that a ratio of at least 1:6 between the circumference of the aryepiglottis and the circumference of the vocal tract produced a strong singer's formant. By narrowing the aryepiglottis, the singer will achieve the twang associated with the SF.

There were interesting presentations on two formant strategies in the male voice (no surprises here) by the great pioneer of vocal acoustics, Johann Sunberg and my excellent NYU colleague, Brian Gill. Brian also made an interesting study of Db5 sung by pop singer David Phelps to show that it is possible to use the high voice well in a non-classical mode.

I was sad to miss two talks on Electro-glottography given by two excellent pedagogue-scientists: Donald Miller of Voce Vista fame and the excellent Viennese voice teacher-biophysicist, Christian Herbst. Now that I reside officially in Europe and must spent more time there, I will visit my colleague Don Miller soon for some needed collaboration and I hope to visit Dr. Herbst soon to pick his magnificent brain. I found his commentary during the sessions most enlightning.

I was also very happy to meet Dr. Ron Scherer again  after a brief meeting some 10 years ago. Dr. Scherer is a very approachable man with a wealth of information that speak directly to the singers experience.  I hope to visit him at Bowling Green State University in Ohio and pick his brain as well.

The presentation that I found the most compelling was given by Pedro Amarante Andrade, a young Brasilian researcher based in England, entitled Analysis of the dynamic mechanisms behind VF muscle contraction in the chest-to-head passaggio.  Mr. Andrade summarized the study by explaining that the vocalis muscle does not become inactive across the muscular passaggio but rather switches its activity from an isotonic to isometric mode. In plain language, the vocalis maintains activity and provides stabilizing resistance to the lengthening of the vocal folds by the crico-thyroid muscle.  This antagonism provides longitudinal tension of the vocal folds, which help produce a quicker, "snapping" close phase of the folds with increased contact area.  Supposedly, this would maintain a richer source tone because of the greater fold mass and a slightly longer open phase, resulting in greater air flow per cycle, yielding greater sound pressure.  There was no measurement of subglottic pressure.  I would predict that subglottic pressure would reduce in comparison with a production whereby CT activity was less opposed by Vocalis.

This is in short what I have been arguing for the past three years.  I have encountered two many tenors in particular who resort to a thin production in the top voice resulting in a monochromatic mode of accessing the top that overtime produces a glottal squeeze. This is symptomatic of many a Rossini tenor of our day.  The falsetto-like approach to the top voice, with less contact area of the vocal folds is not a finished product.  This is what I have labeled my "little voice". With training, the little voice can become fuller (i.e. the CT becomes more able to sustain the isometric resistance of the Vocalis without compromising fold length.). This is perhaps why Pavarotti refers to himself as the first "real tenor voice" to sing the Fille du régiment aria in the original key.  This thinner production also produces a slightly raised larynx making acoustic transition to second formant dominance difficult, since the high larynx raises the first formant, maintaining it dominant across the passaggio.

It is important to keep in mind that the CT maintains a relative dominance after the muscular passaggio, but this musuclar dominance is not unopposed.  I would further theorize that in the lower half of the voice, where the Vocalis has a relative dominance, that the CT also very much involved. A dynamic antagonism between the two main muscle groups is crucial to homogeneity throughout the modal range.  This used to be the goal of great singers of previous generations until idiosyncracies in the voice have become a quick marketing tool for record producers and agents.  It is my hope that Mr. Amarante-Andrade's research mark the beginning of further investigations that will give more objective information on the relationship between muscular balance and longevity in classical singing.

© 08/23/2010

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1 comment:

Martin Berggren said...

I had a great time at the pas5 conference as well and was able to attend most of the talks.

It was interesting to note how many of the presentations that were co-authored by Johan Sundberg, the legend of voice science! He must certianly have had the highest number of co-authored contributions; how impressive to see that level of enthusiasm and curiosity of a 75 year old man that already has contributed so much!

There were many fascinating presentations during the week. A talk that was particularly spectacular, and one that you missed, was given by Mattias Echternach from Freiburg. Echternach and coauthors has been capturing real-time (8 frames/s) MRI pictures of the vocal tract of two tenors, one leggiero and one spinto, at the same time as the sound was recorded by an optical microphone. The nice twist here was that the singers were very good; the claim was that they were among the very best young singers around at present. Of course, we all wanted to know who they were, but so far no luck... One thing that I remembered was the vocal tract changes for the spinto around the passaggio. If I remember correctly (it has already been a few weeks...), we could see how actually the larynx slightly raised with pitch up to the point of turn to F2 resonance when it fell slightly down and continued up (slightly) with pitch. That certainly is consistent with a meticulous tracking of F1 and F2 respectively. I hope to be catch the publication when it comes out!