Operatic vibrato modulates pitch at 5.5-7.5 Hz

Evidence

Trained singers, particularly those with Western operatic voices, exhibit an effect known as “vibrato” in which their f0 is varied at a rate of approximately 5.5 to 7.5 Hz with a range of between ±0.5 and ±2 semitones (Dejonckere et al., 1995). — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1336

The shape of the acoustic excitation spectrum remains essentially constant while singing, although the amplitude change of −12 dB per octave is varied for artistic effect and singing style and to aid voice projection by professional singers (e.g., Sundberg, 1987). The spacing between the harmonics will change as different notes are sung; Figure 4.38 shows three input spectra for sung notes an octave apart. Trained singers, particularly those with Western operatic voices, exhibit an effect known as “vibrato” in which their f0 is varied at a rate of approximately 5.5 to 7.5 Hz with a range of between ±0.5 and ±2 semitones (Dejonckere et al., 1995). — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1336

Categorization

• CANDY: A neat, quotable number: operatic vibrato rate sits around 6-7 Hz — good dinner-table sound trivia.
• QUESTION: Why does vibrato cluster so tightly around this rate — is it linked to a perceptual or physiological optimum?
• corroborated: 3 independent passages support this claim — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1336
• XREF: connects to: Upper harmonics swing more in frequency than lower ones during vibrato; Vibrato produces tremolo when harmonics sweep across resonant peaks; Vibrato varies pitch while tremolo varies loudness during sustained notes. (+2 more)

Broader Connections

• Vibrato varies pitch while tremolo varies loudness during sustained notes. #expands (0.85)
• Upper harmonics swing more in frequency than lower ones during vibrato #expands (0.80)
• Vibrato produces tremolo when harmonics sweep across resonant peaks #expands (0.75)