Kashu-do (歌手道): The Singer’s Formant and the Singer’s Formant Region: Defining "Ring"

Superficial understanding of vocal science is one of the greatest enemies of progress in science-based vocal pedagogy.  When a self-described science-based teacher refers to the acoustic region between 2kHz and 3kHz as the Singer’s Formant, it is not always clear what they mean.  Too often, one will point to one of the 3 potential peaks that lie between 2000 and 3200 Hz and say: “see, there is the ring in the voice!” To this a self-described “Bel Canto” teacher will say, “well I don’t hear much ring!”

The five formants (regions of acoustic strength) in the vocal tract occur approximately around 500Hz, 1000Hz, 2000Hz, 2500 Hz and 3000Hz.  These are not precise numbers and their values shift depending on adjustments (vowel changes) in the vocal tract.  The first formant of the [i] vowel for example lies around 280Hz.  This means that the lowest area of acoustic intensity when the vocal tract is shaped to the [i] vowel is around 280Hz.  When the tract is shaped to [a] the lowest area of acoustic intensity is around 800Hz.  Any space will have acoustic regions that amplify sound. Some concert halls are friendly to high voices and others to low voices.  This is simply a way of explaining the nature of formants.  What is unusual about the human voice as an instrument is that its resonator, the vocal tract, is flexible and changeable.  It can readjust to intensify any given pitch.  The region of the singer’s formant is particularly interesting because the human ear is extremely sensitive to the area between 2000 and 3200Hz.

Now to the argument between the “self-described” science-based teacher and the “self-described” Bel Canto teacher.  The former points to strong energy in the SF area and calls it the ring in the voice.  The latter claims not to hear any ring.  Empirically they would be both correct and therefore paradoxically both wrong in their assessments. The reasoning is the following:  strong energy in the region between 2000 and 3200 Hz will be perceived as particularly strong to the human ear and could be enough to make a singer easily discernible in the presence of an orchestra.  Practically that could be enough (especially given the low expectations of modern day opera).  But to the Bel Canto teacher who seeks a particularly intense experience relative to ring, the mere presence of the upper three formants in strength is not enough.  And so he will discredit the science-based teacher for not understanding the nature of ring.  This would not be entirely wrong.  However, most voices exhibit energy in the SF area precisely in this way and it is enough for most orchestral situations.  Nevertheless, this does not constitute “ring” in the traditional sense, nor does it in fact meet with the scientific definition of “ring”, which  indeed coincides with the results the Bel Canto teacher expects.

The scientific definition of “ring” is not a mere presence of strong energy in the upper formants but rather a cluster effect of two of the three formants.  If we take the note Bb4 (c. 460Hz), the fifth harmonic (5th multiple of the fundamental frequency)  would be at 2300Hz, squarely between the third formant (cir. 2100 Hz) and the fourth (c. 2500Hz).  Effective vocal tract tuning (including, vowel, laryngeal depth and  aryepiglottic fold diameter, etc) would raise the 3rd formant and lower the fourth such that both energies would impact the fifth harmonic.  Most of the vocal energy on the upper part of the spectrum would center on the fifth harmonic.  The third formant of the [u] vowel falls just below 2300 and its fourth formant just above 2300.  This would support a constant assertion by Gioacchino Livigni that the Old School tenors (before Corelli and Del Monaco) tended to pursue this strategy of clustering around the 5th harmonic on notes Bb and above.  A similar strategy is possible on the 6th harmonic (c. 2760 Hz).  This would require tuning the fourth and fifth formants of the back vowels ([u, o, a] respectively up and down to cluster around the 6th harmonic or the third and fourth formant of front vowels ([i, e, E].  This is the strategy of the tenors of the second half of the 20th century.  This is equally viable.  What is not as efficient is spreading the tree formants on three different harmonics.  Because the human ear is particularly sensitive to the SF region (c. 2000-3000 Hz), even if the energy is spread between three harmonics, as long as it is strong, it will have a strong impact on the listener’s ear even with an orchestra.  It will however not be the same powerful impact that is heard from top singers, who by some personal sensitivity can achieve the complex tuning of the vocal tract necessary to cluster the formants as described above.

The fact is that science and tradition agree, if one takes the time to really understand both.  The constant assertion that science is not far along enough to make a difference in vocal pedagogy is just the easy judgment of those who are either not interested in understanding science as deeply as they need to for it to be relevant or are simply afraid to have their techniques proven inadequate.  In truth, science is less there to discredit anyone’s approach, but proactively present to help us refine the approaches dictated by our instincts.  Inspired teachers begin with great instincts.  Great teachers go beyond their instincts and educate themselves with all the available facts.  We must never forget that the most celebrated voice teacher at the height of the Bel Canto period was Manuel Garcia, for whom Rossini composed the role of Conte di Almaviva in Barbiere di Siviglia.  He is the same Manuel Garcia whose son, Manuel Garcia, Jr., invented the first mirror laryngoscope, basically the same tool used by doctors and ENTs for superficial pharyngeal/laryngeal analysis.  Garcia, Jr. is considered the first true science-based voice teacher.

PS.  Since my latest PC computer crashed, I acquired a MAC.  I have tried to calibrate the frequency region of Audacity for spectrographic analysis but to no avail.  It is possible that the version I have has a bug.  I would welcome advice from other MAC users who use Audacity or who have recommendations for another spectrographic analyzer.  Spectrograms would enhance this post but unfortunately Voce Vista does not work with MAC and will not any time soon.


© 08/25/2011

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