Exploring Sound Waves and the
Voice
Lauren Brendel, AP Physics 1
Sound Wave Basics
● Sound is a mechanical, longitudinal wave with
compressions and rarefactions…
● But it can be displayed as a transverse wave
for clearer understanding of its properties
Wave Qualities: Amplitude
● Maximum height/depth of wave crest/trough
above or below the equilibrium point
● Determined by amount of air pressure
● Relates to the volume of the sound: higher
amplitude = louder sound
Wave Qualities: Frequency
● Number of cycles of a wave that move past a
set point in a given amount of time (Hz)
● Determines pitch of a sound: higher frequency
= higher pitch
Frequency and Harmony
● Intervals in music have specific frequency
ratios- this is what makes them sound
consonant (pleasant) or dissonant (unpleasant
or “conflicting”)
● Common consonant interval ratios:




Octave- 2:1 (512 Hz and 256 Hz)
Third- 5:4 (320 Hz and 256 Hz)
Fourth- 4:3 (342 Hz and 256 Hz)
Fifth- 3:2 (384 Hz and 256 Hz)
Wave Qualities: Timbre
● The distinct character, or tone color, of an
instrument or voice that distinguishes it from
other sounds, even at the same pitch and
volume
● Affected by two main factors:


Harmonics- fundamental frequency, dominant
frequency, overtones (partials and harmonics),
etc.
Envelope- attack time, decay, sustain, release
Exploring Timbre with the Voice
● Unique as one voice can produce a large
variety of vocal qualities
● Professional “talkers” (actors, singers, radio
hosts, public speakers, etc.), whether
consciously or not, try to produce a desired
timbre or tone quality that is most pleasing to
their listeners/is most appropriate for the job
at hand
Estill Voice Training
● developed by voice specialist Jo Estill in 1988
● based on “deconstructing the process of vocal
production into control of specific structures
of the vocal mechanism”
● combines methodical speech therapy
techniques with artistry and creativity to
produce consistent levels of vocal quality
Estill Figures for the Voice
There are 13 Estill voice figures:
● True Vocal Folds:
Onset/Offset Control
● False Vocal Cords Control
● True Vocal Folds: Body
Cover Control
● Thyroid Cartilage Control
● Cricoid Cartilage Control
● Larynx Control
● Velum Control
● Tongue Control
● Aryepiglottic Spincter (AES)
Control
● Jaw Control
● Lips Control
● Head and Neck Control
● Torso Control
By using different “settings” of various
combinations of these figures, singers
can create the six Estill vocal qualities.
Estill Vocal Qualities: “Speech”
● exactly what it sounds like- “talking on
pitch”
● found in styles of pop music, jazz,
musical theatre (patter songs), etc.
● Set-up: glottal onset, thick vocal folds,
middle larynx, relaxed head and torso
What Does It Look Like?
Estill Vocal Qualities: “Sob”
● soft, dark sound- name comes from
similarity to a deep crying noise
● used when a more “mature” sound is
desired- classical, older ballads, etc.
● Set-up: thin vocal folds, low larynx,
tilted thyroid, high tongue, anchored
head and torso
What Does It Look Like?
Estill Vocal Qualities: “Twang”
● shouting, resonant sound that can be
made to have a nasal quality as well
● used for “safe shouting” and projecting
effectively, musical theatre “character
voices,” etc.
● Set-up: narrow AES, high larynx, high
tongue, tilted thyroid, thin vocal folds
What Does It Look Like?
Estill Vocal Qualities: “Opera”
● achieves strong opera or classical sound
while maintaining a lot of control
● set-up: combination of thin and thick
folds, tilted thyroid, narrow AES, low
larynx, compressed tongue, anchored
head and torso
What Does It Look Like?
Estill Vocal Qualities: “Belt”
● extremely powerful sound used in pop,
gospel, R&B, and musical theatre styles;
can be extremely harmful to the vocal
cords if done incorrectly
● set-up: glottal onset, thick vocal folds,
tilted cricoid, narrow AES, high larynx,
high tongue, anchored head and torso
What Does It Look Like?
Estill Vocal Qualities: “Falsetto”
● breathy, high-pitched singing; most
commonly associated with men but, in
Estill, can be achieved by both genders
● found in folk, jazz, pop, R&B, etc.
● set-up: stiff vocal folds with aspirate onset, middle larynx, relaxed head and
torso
Notable Similarities
● high larynx versus low larynx: presence
of overtones
● glottals and high larynx: “spikier” waves
● “Sob” and “Opera”: similar set-ups, very
similar overtones/wave shape; “Sob” is
more pure
Questions?