An analysis of consonant and vowel durations and vocal onset timing in professionals’ and students’ singing

Factors that contribute to the perception of good singing include the presence of singer's formant, degree of vibrato, and pitch accuracy. However, the impact of each phoneme’s duration (phoneme length) on singing impression has not yet been fully clarified. This study focused on the characteristic vocal techniques of professional opera singers, particularly phoneme length and vocal onset timing. Using the Japanese song Hana, composed by Rentarō Taki with lyrics by Hagoromo Takeshima, we recorded performances by four professional opera singers and 22 students with no vocal training. We then analyzed the duration of each phoneme and the difference between the score-indicated and actual singing onset (vocal onset timing). The results showed that professionals produced significantly longer word-initial consonants than students. For plosive sounds, professionals tended to significantly shorten the closure phase while extending the aspiration portion in voiceless plosives and the transition to the vowel in voiced plosives. This may help prevent interruptions in the vocal line by reducing silent intervals, while making the plosive sound more prominent. Regarding vocal onset timing, professionals tended to initiate consonants earlier, especially at the beginning of musical subphrases. This suggests that early articulation enhances the clarity and prominence of subphrase onsets.