Can Inexperienced Listeners Hear Who Is Flat? The Role of Timbre and Vibrato

Abstract

Research has shown that the distribution of spectral energy and the presence of vibrato in a complex tone can affect pitch perception. This study sought to answer the questions: "Does timbre affect the perception of difference in pitch in complex synthetic stimuli modeled after singing voices?" "Does vibrato affect the perception of difference in pitch in complex synthetic stimuli modeled after singing voices?" and "Does the direction of timbre difference affect the perception of pitch difference?" This is a repeated-measures factorial design. The experiment consisted of three experimental blocks at the pitches A3, G4, and F5, each with a vibrato and no-vibrato subblock. For each block, two reference stimuli (mezzo-soprano and soprano) and six test stimuli (mezzo-soprano at frequencies of -1%, -2%, and -3%, soprano at frequencies of -1%, -2%, and -3%) were synthesized on the vowel /ɑ/. Each reference stimulus was paired with itself, with the other reference stimulus, and with all the test stimuli. Vibrato stimuli had a rate of 5.6Hz and a frequency vibrato extent of ±50 cents. Listeners indicated the degree to which stimuli differed in pitch. Differences in timbre and vibrato were significant main effects on the perception of pitch difference. The direction of timbre difference was a consistent significant effect on the perception of pitch difference for the pitch G4; however, this was not a consistent effect at the pitches A3 and F5. Numerous factors can affect the perception of pitch including timbre and presence of vibrato.