Objective: Chordo is a traditional multi-part singing performed by the Chinese Mongolian ethnic group. Previous studies have mainly focused on the acoustic and physiological characteristics of its low-pitched throat singing (Kargyraa), but little attention has been paid to an overall comparison between conversational speech and the high and low voice parts of Chordo. This study examines the acoustic characteristics of Chordo singers under three conditions: reading lyrics (RL), high-part singing (HS), and low-part singing (LS).

Methods: The participants were Chordo singers. Two tasks were designed: a vowel task and a song task, with each task being performed under the conditions RL, HS, and LS. In the vowel task, the participants produced seven vowels /ɑ, ə, i, ɔ, ʊ, o, u/, while in the song task, they performed three representative pieces. Audio and electroglottographic (EGG) signals were recorded using PowerLab and LabChart 7. Fundamental frequency (F0), intensity, and formants were extracted using Praat, while open quotient (OQ) and speed quotient (SQ) were measured using KAY Multi-Speech Model 3700.

Results: The results showed that in RL, vocal fold vibration was stable, and vowel separability among the seven vowels was relatively high. In HS, pitch range and amplitude variation increased, with lower OQ and higher SQ, while vowel separability remained largely similar to that in RL. These features contributed to a higher pitch, a brighter timbre, and clearer articulation. In LS, F0 remained low and amplitude was relatively high. The EGG waveform displayed a distinct double-peaked pattern, and the downward formant shift and reduced vowel separability indicate tongue–larynx coupling, resulting in a deep and strong bass vocal quality.

Conclusion: The three conditions RL, HS, and LS used by Chordo singers exhibit distinct acoustic and physiological characteristics. HS primarily emphasizes melodic expression, while LS produces a low, growl-like timbre. This study provides quantitative evidence for the multi-part vocal style of Chordo performance and clarifies the features of speech, singing, and resonance.