Presentation on theme: "The Science of the Singing Voice"— Presentation transcript:
1 The Science of the Singing Voice Overview of the course (HC16)Winter 2008Pat Keating, Linguistics, UCLA
2 BooksJohann 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: Sundberg’s demo Go to: The ugly voice posterBut we don’t 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 slideTone generator in Audacity is another way to relate Hz to notes
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 questions1. 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 ExamplesFrom Worst of AI DVD:From AI on Youtube:
10 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”: steadinessTransitions between notes: swoopingBut we did some of this in the very first class – add what we did then
13 Vibratos Dimensions of vibrato Supposed good classical vibrato Rate, range, amplitude vibratoSupposed good classical vibrato5.5 to 7 Hz rate, + .5 to 2 semitones rangeWhat good a vibrato does, doesn’t do for the singerExamples next slides
18 Lab 2 and Assn 1: vibratos Pitchworks, wavesurfer Measuring F0 from pitchtrackCalculating vibrato properties
19 Tricks in pitchtracking Hardest part: keeping track of F0 range and optimizing option settingsTuning forks and thin voices: don’t use cepstral method, use autocorrelationProblems tracking trills and other fast F0 changes: need to change step size and/or window length
20 3. Larynx and phonationLaryngeal anatomy: physical model, “Vocal Parts” CD, ASA and Painter videotapes, Youtube videos, (DVDs about source and about phonation)Mechanisms of vocal fold vibrationF0 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, wavesurferDVD “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
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/wavesurfComparing spectra of different voice qualities by strength of H1, number of harmonics, extent of high-freq energy
24 5. Resonances From Ladefoged on resonance Basic source-filter idea More of Source-Filter DVD, on filterVowel “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 Hz for basses, for tenors), which allows a solo voice to stand out against an orchestra, or other singersSopranos don’t 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 formantNot 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 peakMale singers: enlarge the ventricle (just above the larynx), lower the larynxIt is not known how altos (or sopranos, if they have one) produce their singers formant
29 Speakers formant More like at 3500 Hz than 3000 Property of speaking voices judged to be goodSeen 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 formanttrying to increase singers formant in own voiceEmphasized looking at /o/, /u/, where higher formants are expected to be weak so any enhancement will be unambiguous
31 6. Vowel formants and F0Average formant frequencies for different English vowelsa 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: Pavarotti’s tenor tuning of F1 to H2 in chest voice, F2 to H3 or H4 on high notes]
32 When F0 is above F1 F0 > F1 for many soprano notes F1 cannot match F0, so H1 can’t be boosted by a resonancevowel qualities are indistinct because F1 is not excitedtrained singers tend to adjust the vowel quality so that the F1 moves up, in the direction of F0
33 F1 and F0F1 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
35 The soprano challengeA few years ago a study of this effect, explicitly testing what Sundberg had said, got a lot of publicity:They found that a trained soprano singing above about 440 Hz tuned every vowel’s 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 tuningHappy Birthday when sung from F4 to F5: not a good match between F0s and F1sAssignment was to write new lyrics that would give a better match to my vowel formants in this keyFull credit for nonsense, but a prize promised for best meaningful lyricsSome 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 lectureGerry Berke from Head & Neck Surgery on their research on neuromuscular control of F0, on vocal pathology, and on care of the voice
41 7. Consonants2 chapters each in Miller, Nair, on different aspects of consonants in singingMiller: oral agility for rapid consonant production
42 7. Consonants Voiced vs. voiceless consonants Effects of voiceless consonants on melodic lineEffect of C voicing on vowel F0Lyricist’s choice of consonants already affects the song, independent of artist’s interpretation
43 Sondheim lyrics example Bernadette Peters, Not a day goes by
44 Consonant “resonance” Nair: More vs less sonorous (vowel-like) consonants (“consovowels”) as seen in the narrowband spectrogramConsonant durationUsing consonant articulation artistically, e.g. for emotion
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
48 8. Vocal warm-upsTitze explains warm-up exercises in terms of bringing all systems up graduallyAcoustic loading for respiratory warm-upincrease 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 startincrease F0 so that Ps must increaseFun with straws
49 9. EGGCh. 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: EGGWe made individual EGG recordings of students’ voicesAssn 6 on EGG analysis
52 Lab 7: webpagesThe course requires a term project, which is presented as a webpage visible to the whole classThis 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. AerodynamicsNormal breathing: about .5 liters 12 times/minute, with active inspiration and passive expiration.Muscles of expansion: external intercostals, diaphragmAs in speech, in singing expiration is actively controlled, first by holding it back, then by increasing itMuscles of contraction: internal intercostals, abs
54 Breathing in singingTrained 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 singer’s 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. pitchthe clear relation of loudness, pressure and pitch in these quicker triads
58 The flow glottogramUg, from inverse filtering of Uo signal
59 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 partialthe maximum closing rate is proportional to the amplitudes of the overtones
60 Breathy phonationthe glottis is somewhat abducted without complete closureso some air flows through continuously, and the maximum flow is quite highhigh airflow = a strong H1 in the sourceHigh airflow also = high-frequency noiseSlower 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 vibrationBut the small and brief glottal opening means that little air flows throughLower Ug means a weaker H1Closing is usually more abrupt, so higher partials are stronger
62 Sundberg’s flow phonation The sweet spot: the most abducted glottis that will still give complete closureMost abducted, to give highest flow and thus strongest H1H1 in flow phonation can be 15 dB or more greater than in pressed phonationComplete closure, to reduce glottal noise and to strengthen higher partials
63 Loudness control witha. phonation: the right amount of vocal fold adduction (Sundberg’s flow phonation)b. the vocal tract: formant tuning, singers formantc. 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