From CCRMA Wiki
1. Perceptual Evaluation of Vibrato Models
- Vincent Verfaille, Catherine Guastavino, Philippe Depalle
- Proceedings of the Conference on Interdisciplinary Musicology (CIM05)
- spectral envelope modulation
- frequency-dependent hysteresis behavior
- test: preference for sounds with modulated spectral envelope
- offers great literature review & background info on vibrato pitch, rate, extent, shape, and temporal evolution
- provides equations for modeling FM, AM, SEM pulsations
- vibrato is made of at least one of these three kind of modulations:
- amplitude modulation (predominant in wind and brass instr)
- frequency modulation (predominant in voice and string instr)
- spectral envelope modulation and hysteresis (existing in wind, brass, voice)
- Questions & thoughts:
- * How much of the analysis is instrument-specific, and how much is it performer/ context/ style-specific?
- * It'd be interesting to see a more music-passage specific (higher level) analysis as opposed to instrument-specific modelling
2. An Investigation of Vocal Vibrato for Synthesis
- Robert Maher, James Beauchamp
- Applied Acoustics 30 (1990) 219-245
- focuses on vocal vibrato & presents a new panned-wavetable synthesis method
- role of spectrum modulation
- findings: "Inclusion of typical random fluctuations of vibrato rate, vibrato depth, and nominal sung frequency resulted in no quality preference over examples with constant values. Inclusion of vibrato-induced spectrum modulation resulted in a substantial improvement over examples having constant spectra."
3. Synthesis of Vibrato Singing
- Yoram Meron and Keikichi Hirose
- 2000 IEEE International Conference on Acoustics
- matches the phase of the vibrato in the original unit (used for synthesis in the source database) with the vibarto phase of the synthesized (target) vibrato sound.
- useful section: 3.1 Vibrato detection
- rate between 4.5 adn 7.0 Hz
- modulation depth between 4% and 15%
- extracted pitch - interpolated extrme points, compare to threshold
- --> sequence of 5+ extreme points which pass all these tests are marked as vibrato anchor points
4. Automatic detection of vibrato in monophonic music
- Hee-Suk Pang, Doe-Hyun Yoon
- Pattern Recognition 38 (2005) 1135-1138
- method that automatically detects vibrato using (1) vibrato rate, (2) extent, and (3) intonation
- potential applications: wav-to-midi conversion
- uses maximum likelihood estimation (understand this..?)
- vibrato existence as product of (1) vibrato rate and (2) normalized vibrato extent probabilities
- Questions & thoughts:
- extend to polyphonic music with a vibrato solo-line? polyphonic music with overall vibrato quality?
- mentions how the recommended coefficient values can (should) be modified depending on musical style... It'd be nice to know how style affects these.
Where to go from here
- take a simple monophonic wav file and try to detect locations where vibrato is used
- characterize parameters of vibratos for different style/ context
- ultimately: try to apply expressive nuances/ vibratos to scores and MIDI files, etc. Try to impart characteristics of "style"
- avoid being instrument-specific
- make it easily applicable to computer-generated sound, ensembles
- aim for a higher level characterization