Updated: Oct 3, 2022
This article is the second in our four-part series on “The Magic of Vocal Harmony” where we briefly explore an aspect of choral singing that sparks the imagination to learn more about the science behind why we sing together.
Humans enjoy listening to beautifully executed vocal harmony. For some of us, singing the harmony is even more enjoyable than merely listening. What draws us to vocal harmony? There could be a social-emotional reason we find the experience of vocal harmony pleasing, such as it imbues a sense of connection and collaboration. A physical benefit could also be a factor in the enjoyment of harmony (see the first article in this series “Choir brings good vibrations” to explore that angle).
What if I were to suggest we are drawn to vocal harmony because singing with others amplifies, compliments, and confirms the harmony we create when we sing alone?
You read that correctly--our own voice generates chords (harmony). Each note we sing is comprised of many pitches. This concept is present in nature and explained by acoustic physics (the science of sound production), but our ears primarily perceive one pitch being sung. Before reading on, watch this very short video by Ben Fillippone where a singer uses a spectrogram to illustrate this concept isolating the numerous pitches inherent in one sung note.
Each note we sing is comprised of many pitches.
Our brains are trained to isolate the fundamental pitch, rather than the series of overtones created in the sounding of every note. The harmonic series (also known as “overtone series”) is the sequence of harmonic frequencies that vibrate simultaneously when a given pitch is sounded. Here is an example of the harmonics that sound when the pitch "A" is played:
For singers, harmonics generate from the vibration of the vocal folds. We perceive the lowest harmonic frequency being sung as the fundamental pitch. The vocal tract (lips, tongue, throat, etc.) then serves as the resonator for the pitch created by the vocal folds. Resonance is when the harmonic from the vocal folds lines up with shape of the vocal tract (formant energy)--the harmonics are boosted, sounding fuller and stronger. Different volumes of these harmonics, impacted by the shape of the vocal tract, determine the timbre (tone color) of the voice. This scientific process is the reason two people singing the same note will sound different. The vocal tract of each person is unique; therefore each singer will amplify different harmonics creating a distinguishing sound. This concept also applies to different instruments and their varying timbres that explain why a cello and trombone sound different..
Exploring the overtones created by your voice is not only accessible to those who study acoustic physics. It is available to everyone as a spectrometer app can be easily downloaded to a phone, tablet, or computer, that measures the frequency of sound. The experience of singing with a spectrometer might generate more questions than it answers, but it is a worthy and enjoyable pursuit.
This very brief exploration of harmony is merely an introduction to acoustics, intended to consider whether our compulsion to seek out creating music with others is to amplify the harmony inherent in our own voices. Our brain seems to prefer when others agree with us, then compliment and magnify our contributions. This short article is merely the beginning of this conversation.
What are the practical considerations of this acoustic conversation for choir? The beauty of this "drawn to harmony" concept theorized above falters when two or more voices cannot agree on the pitches to be sung simultaneously. We have all experienced the discomfort when something sounds “out of tune” or another singer is not producing accurate pitches while harmonizing.
When a singer has difficulty matching pitch, we may assume they cannot hear the pitch (likely due to the term “tone deaf” being inaccurately applied in most of these circumstances.) The reality is the singer struggling to match pitch is hearing all the overtones and have not yet trained their ears to isolate the fundamental. Young male singers may sing an octave displaced when their voices are transitioning. Their vocal tract is physically changing shape due to hormones; thus, their voice is amplifying different harmonics then it did previously. If you refer to the harmonic series graphic above, you will notice the first and third overtones are octaves. Understanding the acoustic situation will help craft a successful solution.
With respect to singers who are matching pitch simultaneously, but the sound is still not cohesive, the role of harmonics could be considered after vowel shape has been unified and vocal technique addressed and practiced. As discussed earlier, each singer has a unique timbre based on the harmonics (a.k.a., partials) their voice amplifies. Some voices amplify higher partials, which result in a brighter vocal timbre, where others might amplify the lower partials, which yield a darker tone quality. There are instances when the harmonic series between two singers may not match easily without one or both singers altering their vocal technique to make the sounds "match". Lining up the overtone series of various singers within the choir can be an inclusive strategy to maximize the frequency energy being produced by the ensemble. To learn more about this technique, you can start by researching the scholarship of James Daughtery, Donald Brinegar, James Jordan, and Amanda Quist. This concept will also be discussed at our "Inclusive Choral Formations" workshop held next month.
Here is a longer video (10 minutes) that explores aspects of this acoustic conversation with choir:
Special thanks to Donald Brinegar who first opened my mind to the world of harmony, intonation, and choral singing from an acoustic perspective.
Articles in our four-part blog series on “The Magic of Vocal Harmony” where each week we briefly explore an aspect of choral singing that sparks the imagination to learn more about the science behind why we sing together.
1 – Choir invites Good Vibrations
2 – Drawn to Vocal Harmon
3 – The Ghosting Soprano
4 – Choral Goosebumps
Disclaimer: these articles may evoke more questions than they attempt to answer.
This series is presented by Sarah Kaufold, Artistic Director of Consonare Choral Community, who holds a BA in Psychology and MM in Choral Music. It was in her undergrad studies where she first began to explore the connections between psychology and music.