I attended a fascinating session, led by Dr. Amanda Quist from Westminster Choir College, that focused on overtones and the harmonic series. This session was, in a word, mind-boggling. The information that Dr. Quist presented totally changed my perceptions of pitch and resonance.
Dr. Quist started the session by speaking to the importance of resonance in choral singing, asserting that it contributes positively to the shared experience of the ensemble. She then began to break down exactly how sounds are constructed (and what determines the resonance of a sound) through the use of a computer program called Overtone Analyzer. The software allows you to import a recording of your singing and then isolate specific formants to hear how they contribute to the sound. Dr. Quist defined a "formant" as "a concentration of potential acoustic energy around a particular frequency region." She explained further that the lower 2 formants determine the vowel of a sound while the pitch is determined by the "Singer's Formant," a clustering of formants 3-5. None of this made sense to me until Dr. Quist played a recording of herself singing a straight tone on a single vowel and took it apart using Overtone Analyzer. When she removed the overtones of the pitch, the vibration was lost and the sound was barely audible. As she added the overtones back in one by one, it started to sound more like the recognizable sound of a human voice. Just as she had explained, the vowel was impossible to discern until formants 1 and 2 were included, and the fundamental pitch was unclear until formants 3, 4, and 5 could be heard. There were loud gasps from the audience as we all came to the mind-blowing conclusion that each individual overtone is equal in importance to the fundamental pitch; without overtones, essential information is lost.
Dr. Quist explained how all of this ties into the concept of resonance: "Resonance occurs when the fundamental pitch or its overtones are aligned with one or more formants." She also explained that manipulating the vowel allows access to different formants. I was amazed to learn how much control an individual singer truly has over the way his or her voice resonates; it's all scientific.
Later on in the session, Dr. Quist had an ensemble come up and sing, and we watched the graphs of their sounds on Overtone Analyzer in real time. She had them sing in all different styles...sometimes breathy, sometimes straight-toned, sometimes with a lot of spin, and with varying dynamic levels...and we were able to see which formants lit up on the screen depending on the group's method of voice production. I was shocked to learn that the straight tone does in fact vibrate in more than one formant, and therefore it is a resonant sound, but not nearly as much so as a sound that has a lot of vibrato, as demonstrated in the video below.
It was incredible to learn about the importance of overtones, and especially about the fact that we have the power to manipulate our overtones in order to change our sound. I also learned that if you can teach the members of your choir to understand the way the voice is constructed, then they can take a scientific approach to producing the desired sound, and the possible range of collective sounds the ensemble could produce becomes almost limitless. This session was certainly an eye-opener! (Or, more accurately, an ear-opener)!
-Juliana Child, Ithaca College '18
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