1. L 17 The Human Voice

2. The Vocal Tract epiglottis
Chicken has Syrinx voicebox (rather than Larynx) located much lower down, just above where the lungs join

4. Oscillator: Air under pressure from the lungs make the vocal folds vibrate. Without the “resonator cavities”, the vibrations sound like lips vibrating, or a trumpet or trombone mouthpiece being “buzzed” (with a central frequency when singing). The tension in the vocal muscles control the pitch.

5. Range of Frequencies for the Normal Speaking Human Voice Males: Hz Females: (men have more dense and longer vocal folds) Singing voices (especially the higher harmonics) extend the range into the kilohertz region.

6. English Vowels
Vocal tract positions for some English vowels. The vowels in heed, hid, head and had are called front vowels, because the highest point of the tongue is in the front of the mouth. The vowels in hod, hawed, hood and who’d are called back vowels. The tongue is highest in heed and who’d, which are called high or close vowels. As to timbre, the vowel of heed seems shrill, while the timbre of who’d seems low and dull.

7. formants Formants: A range of frequencies that are enhanced.
The shape of the envelope determines what vowel you hear!

8. We can model the vocal cavity as a 17cm long conical tube closed at one end (the vocal fold end). Hence the harmonics expected would be fn=n v/2(.17) = 1, 2, 3 kHz, etc. The Q is very low due to the softness of the cavity tissue, so the resonances are rather broad.

9. Different shapes create different formant frequencies

10. Vocal Formants “had” Similar to Hall Fig. 14.8
A 17 cm long (closed) tube has resonances at
f = (2n+1)(340 m/s)/(4*0.17m) = 500 Hz, 1500 Hz,
Due to the soft tissues, these resonances are broad. This is NOT the pitch of speech and singing

11. Pure 250 Hz source (with lots of harmonics)
1 kHz
2 kHz
3 kHz

12. send that 250 Hz sound (with lots of harmonics) through the cone:
"Formant"
1 kHz
2 kHz
3 kHz

13. send that 500 Hz sound (with lots of harmonics) through the cone:
SAME Formant
1 kHz
2 kHz
3 kHz

14. Formant frequencies determine vowel sounds
demo with Raven Lite…

15. What is the frequency of the note?
2 kHz b) 3.1 kHz c) 1.0 kHz d) 250 Hz
1 kHz
2 kHz
3 kHz

16. What is the frequency of first formant?
2 kHz b) 3.1 kHz c) 1.0 kHz d) 250 Hz
1 kHz
2 kHz
3 kHz

17. If I sing a higher note…. 1 kHz 2 kHz 3 kHz
a) the pitch and the formants go up b) the formants go up but the pitch stays the same c) the pitch goes up but the formants stay the same
1 kHz
2 kHz
3 kHz

19. Operatic Tenor & Orchestra
Acoustic power in
formants allow
operatic singer to
be heard over
orchestra.
Plot from D. Hall, Musical Acoustics; tenor is Pavarotti

20. A: Frequency modulation. B: Amplitude modulation.
CT 8.3.2
Musicians refer to tremolo when the loudness fluctuates while the pitch remains unchanged. Is this an example of…
A: Frequency modulation.
B: Amplitude modulation.
85% correct.

21. A: Frequency modulation. B: Amplitude modulation.
CT 8.3.2b
Musicians refer to vibrato when the pitch is wiggled up and down as you sing. Is this an example of…
A: Frequency modulation.
B: Amplitude modulation.
Violinists can make “excursions”
From concert A of .2 semitones,
6 times/sec.
6 Hz -> “signal frequency”
440 Hz -> “carrier frequency”
0.2 semitones-> strength of the
modulation