The Science of the Singing Voice

1
The Science of the Singing Voice

• Overview of the course (HC16)
• Winter 2008
• Pat Keating, Linguistics, UCLA

2
Books

• Johann Sundberg, The Science of the Singing
  Voice. Northern Illinois University Press (1989)
• Peter Ladefoged, Elements of Acoustic Phonetics.
  Second edition. University of Chicago Pres
  (1996)
• Richard Miller, The Structure of Singing System
  and Art in Vocal Technique. Wadsworth Publishing
  (2001)
• Richard Miller, National schools of singing
  English, French, German, and Italian techniques
  of singing revisited. Scarecrow Press (2002)
• Garyth Nair, Voice Tradition and Technology A
  State-of-the-Art Studio. With CD. Singular
  (1999)
• Ingo Titze, Principles of Voice Production (2nd
  printing 2000)

3
1. Intro Sundbergs demo

• Go to The ugly voice poster
• But we dont do any synthesis in the course

4
F0 and pitch

• Vibration, Hz
• Tuning forks, vocal folds
• Relations of Hz to musical notes and intervals
  (several websites with these) see next slide
• Tone generator in Audacity is another way to
  relate Hz to notes

5
Frequencies of piano white keys
6
Digital audio

• SR, QR. compression
• File formats more complicated this year than in
  2006!
• We need song clips with a single voice (no
  instruments or other voices)

7
Review questions

• 1. Which tuning fork has the higher-sounding
  pitch, 392 Hz or 523 Hz?
• 2. What part of the body produces the
  fundamental frequency of the voice?
• 3. The frequency of the note G2 is 98 Hz. What
  is the frequency of G3?
• 4. Is a song on an audio CD or an mp3 player in
  .wav format?

8
Lab 1 audio clips

• Ripping CD tracks to .wav (CDex, CLICC)
• Ripping audio from commercial DVDs (DVDFab
  Decrypter to AnyAudioConverter)
• Ripping audio from YouTube videos (Freecorder)
• Saving .mp3 and various other audio formats as
  .wav (Audacity, CDex, AudioConverter)
• Splitting and saving mono tracks from stereo
  (Audacity)
• File clips kept on our ecampus Discussion Board

9
Examples

• From Worst of AI DVD
• From AI on Youtube

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2. From Sundberg

• How do you experience your own voice?
• Why does a recording of your voice sound
  different to you?
• And, why do you sound better in the shower?

11
Pitch

• Semi-tone about 6 freq difference
• in tune how close to target is close enough
  (about 20 cents for average listener)
• in tune steadiness
• Transitions between notes swooping

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Example steadiness, swooping
13
Vibratos

• Dimensions of vibrato
• Rate, range, amplitude vibrato
• Supposed good classical vibrato
• 5.5 to 7 Hz rate, .5 to 2 semitones range
• What good a vibrato does, doesnt do for the
  singer
• Examples next slides

14
Example D. Fischer-Dieskau
15
Example Leontyne Price
16
Example Joan Baez
17
Example Kelly Clarkson
18
Lab 2 and Assn 1 vibratos

• Pitchworks, wavesurfer
• Measuring F0 from pitchtrack
• Calculating vibrato properties

19
Tricks in pitchtracking

• Hardest part keeping track of F0 range and
  optimizing option settings
• Tuning forks and thin voices dont use cepstral
  method, use autocorrelation
• Problems tracking trills and other fast F0
  changes need to change step size and/or window
  length

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3. Larynx and phonation

• Laryngeal anatomy physical model, Vocal Parts
  CD, ASA and Painter videotapes, Youtube videos,
  (DVDs about source and about phonation)
• Mechanisms of vocal fold vibration
• F0 variation with airflow means pitch and
  loudness are correlated, which singers need to
  learn to decouple

21
4. Spectrum

• The voice source F0 and overtones
• Line spectrum of source
• FFT of output in Audacity, wavesurfer
• DVD Human Speech a key point of this is that
  speed of closing of vocal folds determines
  strength of higher harmonics and thus the
  brightness of the voice

22
Partials, overtones?

• Partials harmonics
• Overtones partials above F0

23
Lab 3 and Assn 2 FFT

• FFT, LTAS in Pitchworks or wavesurfer
• FFT in Audacity View-Plot spectrum (nice for
  comparing effect of window length shows musical
  note of F0)
• Pros, cons of Audacity vs Pworks/wavesurf
• Comparing spectra of different voice qualities by
  strength of H1, number of harmonics, extent of
  high-freq energy

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5. Resonances

• From Ladefoged on resonance
• Basic source-filter idea
• More of Source-Filter DVD, on filter
• Vowel covering lowering the frequencies of
  front vowel resonances so that brightness is more
  matched across vowels

25
Singers formant

• Singers formant extra energy around 3000 Hz
  (Sundberg says 2300-3000 Hz for basses, 3000-3800
  for tenors), which allows a solo voice to stand
  out against an orchestra, or other singers
• Sopranos dont much need a singers formant
  against an orchestra, because any note above
  about B4 will stand out by itself. Similarly for
  amplified singers.

26
Singers formant

• Not an additional formant, but a clustering of
  F3, F4, F5 when they are close together in
  frequency their strengths are mutually enhanced
  and they give one broad strong spectral peak
• Male singers enlarge the ventricle (just above
  the larynx), lower the larynx
• It is not known how altos (or sopranos, if they
  have one) produce their singers formant

27
Miller singers formant
28
Example Fischer-Dieskau (last vowel)
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Speakers formant

• More like at 3500 Hz than 3000
• Property of speaking voices judged to be good
• Seen in some singing voices, especially in styles
  that are more like speaking (e.g. country)

30
Lab 4 and Assn 3 Singers formant

• Looking at own voice and at recordings to see if
  there is a singers formant
• trying to increase singers formant in own voice
• Emphasized looking at /o/, /u/, where higher
  formants are expected to be weak so any
  enhancement will be unambiguous

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6. Vowel formants and F0

• Average formant frequencies for different English
  vowels
• a strong soprano voice matches F0 (H1) to F1,
  while a weak voice has no formant near F0
• Good illustration of this on DVD the good voice
  and the bad voice samples
• Sundberg says that tuning F0 to F1 can add up to
  30dB to the sound level
• other strategies in other ranges Pavarottis
  tenor tuning of F1 to H2 in chest voice, F2 to H3
  or H4 on high notes

32
When F0 is above F1

• F0 gt F1 for many soprano notes
• F1 cannot match F0, so H1 cant be boosted by a
  resonance
• vowel qualities are indistinct because F1 is not
  excited
• trained singers tend to adjust the vowel quality
  so that the F1 moves up, in the direction of F0

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F1 and F0

• F1 is raised by opening the mouth more, or
  shortening the vocal tract (e.g. smiling)
• YouTube videos of Queen of the Night aria singers
  and their mouth contortions on the high notes

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Sundberg F1 tuning when F0gtF1
35
The soprano challenge

• A few years ago a study of this effect,
  explicitly testing what Sundberg had said, got a
  lot of publicity
• http//www.phys.unsw.edu.au/jw/soprane.html
• They found that a trained soprano singing above
  about 440 Hz tuned every vowels F1 to the F0,
  where formants were determined by reflection

36
Dani and Shri at USC MRI study of vocal tract
adjustments that cause these formant shifts
37
Assn 4 F1 tuning

• Happy Birthday when sung from F4 to F5 not a
  good match between F0s and F1s
• Assignment was to write new lyrics that would
  give a better match to my vowel formants in this
  key
• Full credit for nonsense, but a prize promised
  for best meaningful lyrics
• Some wild-card vowels allowed where F0 was not
  near any F1 of mine

38
The winner

• Yay today yay hurray
• yay today yay is in
• Today (na-me) is a-age
• (A-a-age), spring chickin.

39
Lab 5 a total bust

• Tried to watch video en masse in CLICC
• Had planned to make EGG recordings

40
Guest lecture

• Gerry Berke from Head Neck Surgery on their
  research on neuromuscular control of F0, on vocal
  pathology, and on care of the voice

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7. Consonants

• 2 chapters each in Miller, Nair, on different
  aspects of consonants in singing
• Miller oral agility for rapid consonant
  production

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7. Consonants

• Voiced vs. voiceless consonants
• Effects of voiceless consonants on melodic line
• Effect of C voicing on vowel F0
• Lyricists choice of consonants already affects
  the song, independent of artists interpretation

43
Sondheim lyrics example

• Bernadette Peters, Not a day goes by

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Consonant resonance

• Nair More vs less sonorous (vowel-like)
  consonants (consovowels) as seen in the
  narrowband spectrogram
• Consonant duration
• Using consonant articulation artistically, e.g.
  for emotion

45
Example lyrics articulation

• Bernadette Peters again, 2 clips

46
Example lyrics articulation

• Melinda Doolittle vs. Gregorian chant

47
Lab 6 and Assn 5 consonants

• Listening to, looking at, and making consonants
  in different ways

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8. Vocal warm-ups

• Titze explains warm-up exercises in terms of
  bringing all systems up gradually
• Acoustic loading for respiratory warm-up
• increase the acoustic loading on the vocal folds
  with humming, trills, singing into a straw - lets
  the vocal folds vibrate with more abduction, and
  with overall lower Ps for an easy start
• increase F0 so that Ps must increase
• Fun with straws

49
9. EGG

• Ch. 13 in Nair (1999) The Use of the
  Electroglottograph in the Voice Studio by D.
  Miller and H. K. Schutte
• one of the primary aims of training the
  classical singing voice will be to establish the
  habit of complete and abrupt closure, at least in
  mezzo forte and forte
• Seeing this in the EGG waveform

50
Falsetto vs chest voice on i little contact in
falsetto
51
Lab 7 and Assn 6 EGG

• We made individual EGG recordings of students
  voices
• Assn 6 on EGG analysis

52
Lab 7 webpages

• The course requires a term project, which is
  presented as a webpage visible to the whole class
• This year the webpages were by default on
  Googlepages (linked from, but not on, the ecampus
  site)
• In-class instruction on using Googlepages by our
  ITC

53
10. Aerodynamics

• Normal breathing about .5 liters 12
  times/minute, with active inspiration and passive
  expiration.
• Muscles of expansion external intercostals,
  diaphragm
• As in speech, in singing expiration is actively
  controlled, first by holding it back, then by
  increasing it
• Muscles of contraction internal intercostals, abs

54
Breathing in singing

• Trained singers take much longer breaths, and
  more total air in a breath. More of the air in
  the lungs is exhaled by professional singers.
• Trained singers have lower airflow rates in
  singing than do untrained singers, but the same
  airflow rates in speech.
• Trained singers thus have more efficient
  phonation they use less air to get strong vocal
  fold vibrations.

55
Sundberg airflow vs. pitch
sound level (S), subglottal pressure (P) and oral
airflow (A) from a professional singers
ascending scale, showing that pressure increases
a lot as pitch increases, even when airflow is
fairly constant and sound level increases only
somewhat
56
Air pressure in singing

• Classically trained singers have lower subglottal
  pressures than do untrained singers, and these
  pressures are lower in speech as well as singing.
  
• In singing, subglottal pressure is higher for
  louder phonation and for higher pitches A
  doubling of subglottal pressure gives about a
  doubling in loudness, and subglottal pressure
  also about doubles when F0 doubles.

57
Sundberg Ps vs. pitch
the clear relation of loudness, pressure and
pitch in these quicker triads
58
The flow glottogram

• Ug, from inverse filtering of Uo signal

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2 key aspects of the flow glottogram

• the maximum amplitude of the flow is directly
  proportional to H1, the amplitude (in the source,
  not in the output) of the fundamental component
•     and this affects the perceived strength of
  the voice, though not necessarily its overall
  loudness, which instead depends on the strongest
  partial
• the maximum closing rate is proportional to the
  amplitudes of the overtones

60
Breathy phonation

• the glottis is somewhat abducted without complete
  closure
• so some air flows through continuously, and the
  maximum flow is quite high
• high airflow a strong H1 in the source
• High airflow also high-frequency noise
• Slower closing rate lower-energy higher
  partials, which are then covered by noise

61
Pressed phonation

• The glottis is more adducted than normal
• So stronger lung pressure is needed to get
  vibration
• But the small and brief glottal opening means
  that little air flows through
• Lower Ug means a weaker H1
• Closing is usually more abrupt, so higher
  partials are stronger

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Sundbergs flow phonation

• The sweet spot the most abducted glottis that
  will still give complete closure
• Most abducted, to give highest flow and thus
  strongest H1
• H1 in flow phonation can be 15 dB or more greater
  than in pressed phonation
• Complete closure, to reduce glottal noise and to
  strengthen higher partials

63
Loudness control with

• a. phonation the right amount of vocal fold
  adduction (Sundbergs flow phonation)
• b. the vocal tract formant tuning, singers
  formant
• c. lung pressure higher pressure and higher
  airflow through the glottis. The power of the
  glottal source increases by 6 dB for every
  doubling of the lung pressure

64
Lab 8 aero

• Pressure and flow recording by each student
• Did they show the relation of Ps, Uo, and F0
  (with relatively fixed loudness) as in the
  Sundberg example figures?

65
Exam week project presentations

• During the scheduled exam period, students gave 5
  minute overviews of their projects to the class,
  displaying their webpages, which were not due
  until the end of that day