Singing is modeled as vocal-fold excitation filtered by a time-varying vocal tract

Evidence

The input/system/output model for singing consists of the acoustic excitation due to vocal fold vibration (input) and the vocal tract response (system) to give the output. These are usually considered in terms of their spectra, and both the input and system change with time during singing. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1350

Categorization

• DEFINE: Introduces the input/system/output framework, the standard source-filter model of voice production.