age and voice quality in professional singers
TRANSCRIPT
Age and voice quality in professional singersJohan Sundberg1, Marie Niska Thornvik2 and Anna Maria Soderstrom3
1Department of Speech Music Hearing, KTH, Stockholm, 2Department of Speech Pathology, Danderyd Hospital,Danderyd, 3Department of Logopedics, Soder Hospital, Stockholm, Sweden
Log Phon Vocol 1998; 23: 169–176
The effects of aging on singer’s voices were studied in commercial sound recordings of 20 singers, who all had been recordedover a period ranging from their 20s to their 60s. Four recordings were selected, one from each decade. Excerpts from eachrecording were played to a panel of experts who rated the age of the singer. Rated age showed a significant correlation withreal age. The vibrato rate and extent, and the center frequency of a spectrum envelop peak near 3 kHz were measured, andthe relation of these variables to rated and real age was examined. A clear correlation between the vibrato characteristicsand both real and rated age was found.
Key words: singing, age, singer’s formant, vibrato, perception, recording year.
Johan Sundberg, Department of Speech Music Hearing, KTH, SE-10044 Stockholm, Sweden. Tel:+46 8 790 78 73; Fax +468 790 78 54.
ORIGINAL ARTICLE
INTRODUCTION
It is well known that the effects of aging have impor-tant consequences for professional singing. However,as pointed out by Wilder (15), assumptions ratherthan facts seem to prevail in the literature. Onecommon assumption is that high male voices agequicker than low male voices and that female singervoices age quicker than male singer voices (12). Hor-monal factors have been assumed to underlie thesedifferences (15, 3, 12). After menopause, professionalfemale singers report loss of brilliance and vocalintensity as well as of the upper part of the pitchrange (4). Because of the extreme demands on coordi-nation between phonation and respiration, on sen-sory feedback and on neuromuscular control, theeffects of aging can be assumed to be more noticeablein professional singing than in normal speech (12).According to Sataloff (11) a number of age relatedvoice changes contribute to the deterioration of theability to sing professionally, e.g, phonasthenia andproblems with air consumption. Segre (12) also men-tions timbre, pitch problems, and reduced pitch anddynamic ranges.
On the other hand, certain singers possess a re-markable ability to sing professionally even at veryadvanced age. Many singers have made professionalgrammophone recordings over a period of 30 years ormore with the last recordings emanating from their60s. Indeed, at the age of 70 years baritone GiuseppiTaddei performed the taxing leading part in Verdi’s
Falstaff at the Metropolitan Opera and sopranoMagda Olivero made grammophone recordings at theage of 80. This suggests that the vocal effects of agingmay not always limit the singer’s vocal potentials. Italso raises the question as to what extent it is possibleto perceive a singer’s real age from recordings.
Formal investigations of the effects of aging uponthe professional singing voice are rare. Damste et al.(1) compared vibrato rate in one sample tone takenfrom the third and sixth age decades of 7 singers.They found a decrease of vibrato rate in the morerecent recordings in 5 of these singers. Rothman et al.(10) studied acoustically and perceptually vibratocharacteristics in recorded segments of sung samplesproduced at early and late stages of 5 singers’ careers.They found that evidence of vocal decline was notalways due to changes in singers’ vibrato.
In this investigation we analyze how well a profes-sional singer’s age can be perceived from commercialgrammophone recordings. Also, we examine the rela-tion between perceived singer age and certain acousti-cal voice characteristics.
EXPERIMENT
For the experiment four commercial recordings wereselected of each of 20 professional singers, four ofeach of the classifications bass, baritone, tenor, alto/mezzo soprano and soprano. All singers were ofworldwide fame and representing the western oper-
© 1998 Scandinavian University Press. ISSN 1401-5439 Log Phon Vocol 23
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J. Sundberg et al.170
Fig. 1. Age of the singers, rep-resented by lines, at the record-ings of the examples chosen forthe listening test.
Fig. 2. Acoustic analyses of asung tone. In the spectrogramabove, the symbols T and Arepresent the duration and themean peak-to-peak amplitude,respectively, of 3 vibrato peri-ods. Vibrato rate was mea-sured as the inverse of themean vibrato period (in thiscase 1/(T/3) Hz). A representsvibrato extent expressed in thelogarithmic cent unit. Thelower panel, showing a long-term average spectrum of asinger’s voice, illustrates howthe center frequency of thesinger’s formant SFMidF wasdetermined.
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Rated age of singers 171
Fig. 3. Comparison between thesingers’ real age and the meanrated age.
atic tradition. For one of the singers, however, onlythree recordings were found. As some of the singersare still alive and would wish to remain anonymous,we refrain from revealing their identity.
As illustrated in Fig. 1, the chosen recordingsemanated from different stages of the singers’ careers,encompassing a time period of about 30 years. Thelatest recording emanated from when the singer wasbetween 56 and 76 years and the three preceding oneswere approximately evenly spaced about 10 yearsapart in time, extremes 6 and 16 years. Wheneverfeasible, music from a similar genre was chosen foreach singer. The singer’s age at the earliest recordingvaried between 25 and 35 years, mean 30.2 years.
Because of the size of the material—a total of 79recordings—it was necessary to select short passages,no longer than about 20 sec from each recording.
Passages containing pitch and loudness extremes wereavoided. If the singer had recorded the same songseveral times, the same passage was chosen in allrecordings.
Two listening experiments were carried out. Oneaimed at determining the perceived age of the singers.As the recordings emanated from a period of 70years, approximately, the sound quality differed con-siderably between the stimuli. For this reason, itcould not be excluded that the listeners based theirage ratings on the perceived age of the recording. Asecond listening experiment was, therefore, carriedout in which the listeners were asked to rate the yearof the recordings. In each experiment there were 16expert listeners of similar backgrounds, age distribu-tion and competence. The subjects were singers,singing teachers, voice coaches, or other types ofexpert listeners.
A test tape was prepared for each of the twolistening experiments. On the tape all four examplesfrom the same singer appeared in randomized se-quence. A pause of 5 sec separated the samples fromthe same singer. The pause between sequences wasalso 5 sec. The sequences of 3 of the singers appeared2 times on the tape. The first two sequences on thetape, from a male and a female singer, respectively,were presented only to let the subjects familiarizethemselves with the task and experimental situation.The entire tape thus contained 25 sequences contain-ing a total of 99 examples. The total duration of eachtape was 40 min.
The tapes were played on a Sony DAT recorderand presented to the subjects over ear phones. Thelisteners were asked to rate the age of the singers andthe recording year, respectively, by means of markson 10 cm long visual analogue scales, where theendpoints represented 20 and 70 years and therecording years 1920 and 1990, respectively.
Fig. 4. Comparison between the real and the meanrated year of recording.
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Fig. 5. Comparisons between the mean rated age and the vibrato rate for female and male singers (left andright panel).
Fig. 6. Comparisons between the singers’ real age and the vibrato rate for female and male singers (left andright panel).
ANALYSIS
Perceptual
The intrasubject reliability was analyzed in terms ofthe linear regression of scatter plots showing the samesubject’s first and second ratings of the same 12examples. In the first test, where listeners rated singerage, the correlation coefficients averaged across sub-jects was r=0.59, SD=0.19, extremes 0.93 and 0.18.In the second test, where listeners rated the year ofrecording, the corresponding vales were r=0.78,SD=0.16, extremes 0.47 and 0.98. This result shows
that the ability to rate a singer’s age varied substan-tially between the listeners.
Acoustical
Vibrato rate and extent were measured from KAYDSP Sonagraph analysis of the recordings (see Fig.2). For each singer, a tone containing at least 8vibrato cycles was chosen, if possible from the listen-ing tape. The 4 final vibrato periods were discarded,as vibrato rate tends to increase at the end of sungtones (7). To measure vibrato rate the summed dura-
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Rated age of singers 173
Fig. 7. Comparisons between the mean rated age and the vibrato extent for female and male singers (left andright panel).
tion of the remaining vibrato undulations was mea-sured. This duration was then divided by the numberof undulation periods included and then inverted.The vibrato extent was measured as the mean peak-to-peak amplitude of the same F0 undulations.
Using a narrow band analysis on the sonagraph,the center frequency of the singer’s formant and thefrequency of the second formant were determined forthe male singers. No attempts were made to measurethe frequency of the first formant, however, since thisformant was often impossible to distinguish from thefundamental. Data were collected from four spectrumsections for each of the vowels [i:], [a:] and [u:] andaveraged. In all these vowels fundamental frequencywas lower than 300 Hz. No corresponding data werecollected for the female singers.
Statistical
The material of acoustic and perceptual results (8females×12 males×4 ages, vibrato rate and extent,center frequency of singer’s formant) was submittedto correlation analysis.
RESULT
The effects of age on the voice is likely to be quitespecial in our material, since it contained only singerswho presumably failed to show typical vocal signs ofaging; singers who sound old are not likely to getrecording contracts. For this reason the relationsbetween rated age and voice characteristics seemmore interesting than the relation between real ageand voice characteristics.
Rated age
For each example, mean and SD were computedacross all listeners’ age ratings. Fig. 3 compares theseratings with the singers’ real age. There was a signifi-cant correlation between rated and real age for fe-male singers (r(32)=0.783, pB0.001) and for themale singers (r(47)=0.728 pB0.001). This indicatesthat although the examples were rather short, thelisteners were still able to make a reasonable rating ofthese singers’ ages. Age was overestimated for youngsingers and underestimated for old singers; at least inpart this would be a consequence of the regressioneffect, since correlation coefficients are always smallerthan 1.0. Still, it seems reasonable to assume that alsothe aging of these voices proceeded slower than nor-mal; as mentioned it is unlikely that singers whosound clearly old are engaged for phonogramrecordings.
Rated recording year
For each example, mean and SD were computedacross all listeners’ ratings of recording year. Fig. 4compares the rated with the real recording years.There was a significant correlation between rated yearof recording and the real year of recording (r(79)=0.766, pB0.001). This suggests that the listeners werealso able to rate the recording year with surprisingaccuracy. To test the significance of this ability to theratings of singer age, a correlation analysis was car-ried out where the rated recording year was con-trolled for. The result showed that the correlationbetween rated and real age was still significant
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Fig. 8. Comparisons between the mean rated age and the center frequency of the singer’s formant for the malesingers for the vowels [i:], [u:], and [a:] (left, right and lower panel).
(r(76)=0.724, pB0.001). This implies that the ratedrecording year had no influence on the correlationbetween real and rated age.
Relation to acoustic parameters
The two vibrato parameters as well as the centerfrequency of the singer’s formant in the vowels [i:],[u:], and [a:] all showed significant (pB0.05) correla-tions with rated age, as can be seen in Table 1.
The correlations between rated age and vibratorate and extent were comparatively strong. As illus-trated in Fig. 5a and b, the change of vibrato rate
with rated age varied greatly between the singers. Onaverage the decrease was 0.6 Hz per decade of ratedage for the female singers and slightly less for themale singers. The corresponding value for thesesingers’ real age was smaller, only 0.3 Hz per decade(see Fig. 6a and b). The results corroborated Shipp’s(13) observation that female singers show a slightlyhigher average vibrato rate than male singers. Inter-estingly, when the year of recording was controlledfor, this correlation disappeared completely for thefemale singers and decreased for the male singers. Itis possible that the preferred vibrato rate has de-
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Rated age of singers 175
Table 1. Correlation coefficients (r) and slope of bestlinear fits between rated age and acoustic parameters.N=number of recordings, p=probability
r p SlopeN
Males−0.514 B0.001 −0.049Vibrato rate 47
0.418 0.003Vibrato extent 4.0247Mid FSF
[i:] −10.50.023−0.33147[u:] 46 0.299 0.044 −9.84[a:] 47 −12.60.407 0.005
FemalesVibrato rate 32 −0.057−0.470 0.007
3.33Vibrato extent 32 0.398 0.024
It is quite interesting to compare the dependence ofvibrato rate and extent and of the center frequency ofthe singer’s formant on rated and real age. In allcases the correlation with rated age was clearly higherthan the correlation with real age. Still, the distribu-tion of rated age was narrower than the distributionof real age. This supports the observation that thereis a rather strong relationship between acousticparameters and rated age (8, 9). According to Hollien(4) age can be estimated from tape recordings ofspeech with an accuracy of about 95 years. For oursingers the mean difference between rated and realage was +7 years and −12 years for voices per-ceived as young and elderly, respectively. It may berelevant that these voices can be assumed to becomparatively unaffected by age. It would be interest-ing to compare these values with a population ofchoral singers, where age effects would be consideredmore acceptable.
The center frequency of the singer’s formantshowed a rather weak correlation with rated age. Thisrelation may reflect a descent of the larynx withincreasing age, as such a descent should lower allformant frequencies (14). The center frequency of thesinger’s formant was measured on 4 spectrum sec-tions from each of the vowels [i:] [u:] and [a:]. In somecases the singer’s formant consisted not of one singlepeak but of two peaks with rather different ampli-tudes, so the center frequency was sometimes hard todetermine. Probably these difficulties decrease if longterm average spectra are used (2).
CONCLUSIONS
The age of professional singers can be determinedfrom short voice samples with an error of about +7and −12 years for voices sounding young and el-derly, respectively. For our group of singers, who hadbeen recording professionally over a period of at least30 years, the age was overestimated for young singersand underestimated for the older singers; this effectmay have been enhanced by the regression effect. Therated age correlated with vibrato rate and extent andwith the center frequency of the singer’s formant. Theresults corroborated the general observation that withincreasing age vibrato rate decreases and vibratoextent increases. The effect on the singer’s formantsuggests that the larynx descends slightly with in-creasing age.
ACKNOWLEDGEMENTS
This article is a condensed and revised version of thesecond and third authors’ master thesis, made withthe first author as supervisor. The authors are in-
creased somewhat over time; such a change of prefer-ence may hide a relationship between rated singer ageand vibrato rate.
Fig. 7a and b shows the corresponding values forvibrato extent. Again the scatter is considerable,probably reflecting artistic use of vibrato extent as anexpressive means. An increase of vibrato extent withrated age is demonstrated most clearly in the altovoices; on average vibrato extent grew by about 33and 40 cent per decade of rated age for the femaleand male singers. The dependence on these singer’sreal age was smaller, only 16 cent per decade. Thefemale singers showed a clearly wider extent than themales.
Fig. 8 shows the variation of the center frequencyof the singer’s formant for the male singers. Theoverall trend was that this frequency dropped withrated age. The mean decrease was about 100 Hz perdecade. There was no relation between these valuesand these singers’ real age.
No correlation was found between the frequency ofthe second formant and rated or real age.
DISCUSSION
Our results regarding the change in vibrato rate agreereasonably well with the findings of Damste et al. (1).He found a mean decrease of vibrato rate for his 7singers of 0.53 Hz over a 30 year period. In oursingers the decrease was slightly greater, 0.3 Hz perdecade or 0.9 Hz over a period of 30 years. Interest-ingly, the decrease with rated age was greater, 0.6 Hzper decade. Rated age also correlated with vibratoextent. This correlation is probably quite strong, as itwas not concealed by the dependence of this sameparameter on pitch and vocal loudness shown inprevious research (5, 6).
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debted to Britta Hammarberg for excellent advice, toJoachim Westerlund for statistical analysis and toLars Walldof and Bengt Pleijel for help in supplyingrecordings. Hans Dotevall offered valuable sugges-tions on an earlier version of this article.
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15. Wilder CN. Vocal aging. In: Weinberg B, editor. Tran-scripts of the Seventh Symposium on the Care of theProfessional Voice. Part 2. Life-span changes in thehuman voice. New York: The Voice Foundation, 1978.
SAMMANFATTNING
Effekter a6 aldrande pa sangarroster
Effekter av aldrande pa sangarroster studerades i ca20 sek langa avsnitt av fyra inspelningar gjorda avfyra sangare av vardera kategorierna sopran, alt,tenor, baryton och bas. Inspelningarna var ungefarjamnt fordelade over sangarnas 20- till 60-arsalder(Fig. 1). I en perceptuell analys, dar lyssnarexpertergissade sangarens alder, forelag en korrelation mellanuppskattad och verklig alder (Fig. 3). En akustisksonagramanalys gjordes av vibratots hastighet ochomfang samt, for de manliga sangarna,sangformantens mittfrekvens, dvs spektrumenvelops-toppen vid 3 kHz. Resultaten relaterades till uppskat-tad och verklig alder. Analysen visade att vibratotshastighet avtog med ca 0,6 Hz per dekad uppskattadalder (Fig. 5), och dess omfang okade med i genom-snitt 33 och 40 cent per dekad uppskattad alder (Fig.7) for manliga respektive kvinnliga sangare. Effek-terna var mindre om de relaterades till dekad verkligalder (Fig. 6). Sangformantens mittfrekvens hos man-liga sangare tenderade att sjunka med ca 100 Hz perdekad uppskattad alder (Fig. 8), mojligen beroendepa en aldersbetingad larynxsankning.
YHTEENVETO
Ikaantymisen 6aikutus lauluaaneen
Tutkittiin ikaantymisen vaikutusta sopraano-, altto-,tenori-, baritoni- ja bassolaulajan aaneen. Kutakinaanityyppia edusti nelja laulajaa, joilta koottiin neljan. 20 s mittaista aaninaytetta. Naytteet edustivatsuunnilleen tasavalein laulajien aania 20:n ja 60:nikavuoden valilla (kuva 1). A8 aniammattilaisten kuu-lonvarainen arvio laulajan iasta korreloi todellisen iankanssa (kuva 3): Tehtiin akustinen analyysi vibra-tonopeudesta ja laajuudesta ja mieslaulajille lisaksilauluformantin taajuuden mittaus. Tuloksia verrattiinikaarvioon ja todelliseen ikaan. Vibratonopeudentodettiin hidastuneen n. 0,6 Hz kymmenta arvioituaikavuotta kohti (kuva 5) ja sen laajuus kasvoi ianmukana (kuva 7). Vaikutus oli pienempi verrattaessakronologiseen ikaan (kuva 6). Miesten lauluformantiilaski n. 100 Hz arvioitua ikavuosikymmenta kohti(kuva 8) mahdollisesti liittyen ian mukana tapahtu-vaan kurkunpaan laskuun.
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