Effects of Solo and Choral Singing Modes on Vibrato Rate, Extent, and Duration Exhibited by Undergraduate Female Singers

This study explored potential changes in vibrato among female undergraduate singers (N = 30) majoring in voice performance (n = 15) and choral music education (n = 15) as they transitioned between solo and choral singing modes. Participants sang the same contrasting excerpts (N = 2) from standard choral literature. Each of these singing contexts included a soprano solo and a fourpart choral harmonization where the soprano line used the same musical material as the solo. Both singing mode (solo or choral) and singing context (which of the two musical excerpts) were counterbalanced among participants to control for potential order effects. As they performed individually, participants heard pre-recorded accompaniments and chorus voices presented to one ear via headphone. The other ear remained uncovered for participants to receive acoustic feedback from their own voices as they sang. Results indicated significant differences between the solo and choral singing modes across three measurements of vibrato (faster rate, wider extent, and longer duration of vibrato) in both singing contexts, with no significant differences according to major area of study. Responses to a brief questionnaire administered following the recorded singing trials indicated that all participants (100%) believed singers needed to make vocal adjustments between solo and choral singing modes, with half (50%) of the participants citing blend (50%), followed by volume or dynamics (47%), and vibrato (37%) adjustments. When asked specifically about the singing tasks for this study, 83% of participants stated they actively adjusted their vocal techniques between singing modes, with half (50%) of the participants mentioning vibrato (50%), followed by volume/dynamics (37%), and blend (17%) adjustments. Seventeen participants (57%), however, reported that they did not actively adjust their vocal techniques according to the contrasting nature of the two musical excerpts sung.