The sound of the talking or singing voice is produced by the vocal cords together with the vocal tract. When air is expelled through your throat, the vocal cords vibrate. For an adult man, this vibration has a fundamental frequency of about 110 Hz, with harmonics at 220 Hz, 330 Hz, 440 Hz,.... Sound with components at all these frequencies then passes through the vocal tract (Fig. P13.67A), which can be modeled as two pipes, one representing the larynx and another representing the oral cavity. When making the sound “ah” as in the word father, the larynx acts approximately as a pipe closed at both ends (with just small openings at the vocal cords and the entry to the oral cavity), while the oral cavity acts as a pipe that is open at one end (at the lips). The resonant frequencies of these two “pipes” then affects which of the harmonics of the vocal cords are strongest in the final sound. Figure P13.67B shows the spectrum of the vowel sound “ah”; the strongest harmonics are near 750 Hz, 1100 Hz, and 2500 Hz. These peaks in the spectrum are called formants. If the larynx has a length of 16 cm and the oral cavity a length of 11 cm, which harmonic of which section of the vocal tract gives rise to each of these formants?

Figure P13.67

 

Transcribed Image Text:

750 [ah] as in father 1100 11 cm- 2500 16 cm Oral cavity 2000 1000 3000 Frequency (Hz) Vocal cords Loudness B.