A study was conducted to capture the vocal signals of eight American singers as subjects under multiple tasks (vowel scales, self-defined pitch exercises, given pitches, song singing and natural speech). And seven categories of core acoustic parameters were extracted. The parameters include the resonance peaks that reveal the shape of the cavity, the fundamental frequency that determines pitch, the range that reflects the capacity of the vocal folds, the fundamental frequency perturbation and the resonance peak perturbation to assess stability, and the average energy that represents the intensity of the sound. For the vowel in male voices, the first resonance peak peak value shifted leftward from the standard 717 Hz to 589 Hz in the absence of oral resonance, whereas the third resonance peak F3 of in female voices fell from the standard vocalization of 3088 Hz to 1990 Hz in the absence of head resonance. In the absence of head resonance, the area of the vowel space of the female voice, VSA, was expanded to 177,762 Hz², which is 48 times of the standard value, and the resonance concentration rate, FSA, is 48 times the standard value. Times the standard value, while the resonance peak concentration ratio FCR decreased from 1.682 to 1.405.Once the support of the critical resonance cavity is lost, the vocal tract modulation becomes misaligned, resulting in a significant loss of articulatory clarity.
