Vocal tract resonance multiplies each vocal fold harmonic to shape the sung vowel spectrum

Evidence

The output is the result of the response of the vocal tract for the vowel in fast acting on the input vocal fold vibration. The effect of this is to multiply the amplitude of each harmonic of the input by the response of the vocal tract at that frequency. This effectively imparts the formant peaks of the vocal tract response curve onto the harmonics of the input spectrum. In this example, there are three formant peaks shown, and it can be seen that in the cases of the lower two notes the formant structure can be readily seen in the output, but that in the case of the highest note the for­ mant peaks cannot be identified in the output spectrum because the harmon­ ics of the input are too far apart to represent clearly the formant structure. — David Howard, Jamie Angus, coustics and Psychoacoustics, 1367

Categorization

• DEFINE: Explains the multiplicative input/system/output mechanism that connects vocal fold spectrum to perceived vowel formants.