title: Acoustic parameters critical for an appropriate vibrato.
abstract: BACKGROUND
  A plethora of investigations have studied the acoustic characteristics of vibrato such as the rate, extent, onset (time from initiation of phonation until the first peak of vibrato), and periodicity. Despite extensive research, the degree to which various parameters of vibrato contribute to its acceptability remain unclear.
  
  
  OBJECTIVE
  The present study sought to determine the psychoacoustical relationship of mean fundamental frequency (f(0)), modulation frequency (f(f0m)), modulation depth (d(f0m)), and intensity to the appropriateness or inappropriateness of vibrato.
  
  
  METHODS
  Phonation samples of eight voice majors singing at low, middle, and high pitches were obtained. A high fidelity vocoder (STRAIGHT; Kawahara, 1997) was used to resynthesize these vowels with systematic manipulations of f(f0m) and d(f0m) of the f(0) contours resulting in a total of 600 stimuli (8 singers×3 pitches×5 f(f0m) levels×5 d(f0m) levels). Nine listeners (four experts and five students) evaluated these stimuli for appropriateness of vibrato at two different presentation levels (70 and 90 dB sound pressure level).
  
  
  RESULTS
  Statistical analyses of the perceptual data suggest that appropriateness of vibrato tends to increase with mean f(0) and decrease with d(f0m.) Appropriateness of vibrato is greatest for f(f0m) value of 6 Hz, but decreases both above and below this frequency.
  
  
  CONCLUSIONS
  perceived appropriateness of vibrato results from an interaction of mean f(0), f(f0m), and d(f0m) of the vowel waveform.
authors.affiliation: Department of Speech, Language, and Hearing Sciences, University of Florida, Gainesville, Florida 32611, USA. supraja.anand@ufl.edu
authors.forename: Supraja
authors.initials: S
authors.lastname: Anand
authors.forename: Judith M
authors.initials: JM
authors.lastname: Wingate
authors.forename: Brenda
authors.initials: B
authors.lastname: Smith
authors.forename: Rahul
authors.initials: R
authors.lastname: Shrivastav
mesh_terms: D000162:Acoustics; D000368:Aged; D000465:Algorithms; D000704:Analysis of Variance; D001696:Biomechanical Phenomena; D006801:Humans; D008875:Middle Aged; D009146:Music; D010699:Phonation; D010898:Pitch Perception; D011571:Psychoacoustics; D012815:Signal Processing, Computer-Assisted; D063346:Singing; D013018:Sound Spectrography; D013997:Time Factors; D014732:Vibration; D014833:Voice Quality