Age-Related Changes in Long-Term Average Spectra of Children's Voices


      This paper forms part of a larger study into the nature of singing development in children. The focus here is on an investigation of age-related changes in long-term average spectra (LTAS). Three hundred and twenty children in age groups 4–11 years learned a song. Each child was then digitally recorded singing alone. LTAS curves were calculated from the recordings of each voice and perceived age was estimated by a panel of independent judges. Progressive statistically significant changes were observed in the LTAS as a function of increasing age of the children. These took the form of increases in spectral energy in all frequencies below 5.75 kHz, with concomitant reductions of energy in frequency regions above this point. Increases with age were also found in overall intensity levels of the vocal products. Four experienced listeners audited the voice samples and made estimates of the children's ages. The level of accuracy of age-estimates was remarkably high for children in the youngest age groups, but was reduced with voice samples from older children. Maturation and developing competence of the vocal system, both in growth of lung capacity and at a laryngeal level, are implicated in the generation of age-related spectral changes. Perceived child singer age appears to be less closely related to spectral characteristics (as defined within LTAS) with increasing age of children.

      Key Words

      To read this article in full you will need to make a payment


      Subscribe to Journal of Voice
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Tanner K.
        • Roy N.
        • Ash A.
        • Buder E.H.
        Spectral moments of the long-term average spectrum: sensitive indices of voice change after therapy.
        J Voice. 2005; 19: 211-222
        • Majewski W.
        • Hollien H.
        Speaker identification by long-term spectra under normal and distorted speech conditions.
        J Acoust Soc Am. 1977; 62: 975-979
        • Zalewski J.
        • Majewski W.
        • Hollien H.
        Cross correlation of long-term speech spectra as a speaker identification technique.
        Acustica. 1975; 34: 20-24
        • Wendler J.
        • Rauhut A.
        • Kruger J.
        Classification of voice qualities.
        J Phonet. 1986; 14: 483-488
        • Idzebski K.
        Overpressure and breathiness in spastic dysphonia.
        Acta Otolaryngol. 1984; 97: 373-378
      1. Prytz, S. Long-time average spectra (LTAS) analyses of normal and pathological voices. In: Proceedings of 17th Congress IALP, Copenhagen, 1978, pp. 459–475.

        • Hartl D.A.
        • Hans S.
        • Vaissiere J.
        • Brasnu D.A.
        Objective acoustic and aerodynamic measures of breathiness in paralytic dysphonia.
        Eur Arch Otorhinolaryngol. 2003; 260: 175-182
        • Linville S.E.
        • Rens J.
        Vocal tract resonance analysis of aging voice using the long term average spectra.
        J Voice. 2001; 15: 323-330
        • De Jonkere P.H.
        Recognition of hoarseness by means of LTAS.
        Int J Rehabil Res. 1983; 6: 343-345
        • Master S.
        • De Blaise N.
        • Pedrosa V.
        • Chiari B.M.C.
        The long-term-average-spectrum in research and in the clinical practice of speech therapists.
        Pro-Fono Rev Attual Cient. 2006; 18: 111-120
        • Bladon A.
        Acoustic phonetics, auditory phonetics, speaker sex and speech recognition—a thread.
        in: Fallside F. Woods A. Computer Speech Processing. Prentice-Hall, Englewood Cliffs, NJ1983: 29-38
        • Klatt D.H.
        Detailed spectral analysis of female voice.
        J Acoust Soc Am. 1986; 81: S80
        • Klatt D.H.
        • Klatt L.C.
        Analysis, synthesis and perception of voice quality variations among female and male talkers.
        J Acoust Soc Am. 1990; 87: 820-857
        • White P.
        Long-term average spectrum (LTAS) analysis of sex- and gender-related differences in children's voices.
        Logop Phoniatr Vocol. 2001; 26: 97-100
        • Hurme P.
        • Pirinen M.
        Assessing variation in long-term average spectra of speech.
        in: Ikonen U. Tikkla T. Studies in Language 1: Papers for 12th meeting of Finnish Phonetician. Univ. Joensuu, 1984: 23-36
        • Blomberg M.
        • Elenius K.
        Speech analysis. Statistical analysis of speech signals.
        Quart Prog Stat Rep. KTH. 1970; 4: 1-8
        • Jansson E.V.
        Long-time-average-spectra applied to analysis of music: Part III. A simple method for surveyable analysis of complex sound sources by means of a reverberation chamber.
        Acustica. 1976; 34: 277-280
        • Jansson E.
        • Sundberg J.
        Long-time-average spectra applied to analysis of music: Part I. Method and general application.
        Acustica. 1975; 34: 15-19
        • Sundberg J.
        Long-time-average-spectra of music.
        Acustica. 1976; 34: 270-274
        • Sundberg J.
        • Jansson E.
        Long-time average spectra applied to analysis of music: Part II. An analysis of organ stops.
        Acustica. 1976; 34: 269-274
        • Novak A.
        • Vokral J.
        Acoustic parameters for the evaluation of voice of future voice professionals.
        Folia Phoniatr Logop. 1995; 47: 279-285
        • Welch G.F.
        • Howard D.M.
        Gendered voice in the cathedral choir.
        Psychol Music. 2002; 30: 102-120
        • Mitchell H.F.
        • Kenny D.T.
        The effects of open throat technique on long term average spectra (LTAS) of female classical voices.
        Logop Phoniatr Vocol. 2004; 29: 99-118
        • Pinczower R.
        • Oates J.
        Vocal projection in actors: the long-term average spectral features that distinguish comfortable acting voice from voicing with maximal projection in male actors.
        J Voice. 2005; 19: 440-453
        • Kenny D.T.
        • Mitchell H.F.
        Acoustic and perceptual appraisal of vocal gestures in the female classical voice.
        J Voice. 2006; 20: 55-70
        • Fant G.
        Acoustic analysis and synthesis of speech with applications to Swedish.
        Ericsson Technics. 1959; 1
        • Tarnozky T.
        • Fant G.
        Some remarks on the average speech spectrum.
        Speech Transmission Laboratory, Quart Prog Stat Rep (RIT). 1964; 4: 13-14
        • Ternström S.
        LTAS characteristics of different choirs in different rooms.
        Voice. 1993; 2: 55-77
        • Mendoza E.
        • Muñoz J.
        • Naranjo N.N.
        The long-term average spectrum as a measure of voice stability.
        Folia Phoniatr Logop. 1996; 48: 57-64
        • Kitzing P.
        • Akerlund L.
        Long-time average spectrograms of dysphonic voices before and after therapy.
        Folia Phoniatr. 1993; 45: 53-61
        • Gramming P.
        • Sundberg J.
        • Ternstrom S.
        • Leanderson R.
        • Perkins W.H.
        Relationships between changes in voice pitch and loudness.
        J Voice. 1988; 2: 118-126
        • Bohme G.
        • Stucklich G.
        Voice profiles and standard voice profiles of untrained children.
        J Voice. 1995; 9: 304-307
        • Sundberg J.
        What's so special about singers?.
        J Voice. 1990; 4: 107-119
        • Wendler J.
        • Doherty E.T.
        • Hollien H.
        Voice classification by means of long-term speech spectra.
        Folia Phoniatr. 1980; 32: 51-60
        • Morosow W.P.
        Biofisitcheskie Osnowy Vokalnoi Retschu.
        Nauka, Leningrad1977 ([cited in Wendler et al, 34])
        • Cleveland T.F.
        • Sundberg J.
        • Stone R.E.
        Long-term-average spectrum characteristics of country singers during speaking and singing.
        J Voice. 2001; 15: 54-60
        • White P.J.
        Formant frequency analysis of children's voices using long-term average spectrum.
        J Voice. 1999; 13: 570-582
        • Whiteside S.P.
        • Hodgson C.
        Some acoustic characteristics in the voices of 6–10 year-old children and adults: a comparative sex and developmental perspective.
        Logop Phoniatr Vocol. 2000; 25: 122-132
        • Welch G.F.
        Vocal range and poor pitch singing.
        Psychol Music. 1979; 7: 13-31
        • Boesma P.
        • Weenink D.
        PRAAT v.4.5.01.
        Institute of Phonetic Science, University of Amsterdam, 2006 (Available at:) (Last accessed January 7, 2007)
        • Nolan F.
        The Phonetic Bases of Speaker Recognition.
        C.U.P., Cambridge1983
        • Bloothooft G.
        • Plomp R.
        Spectral analysis of sung vowels II: the effect of fundamental frequency on vowel spectra.
        J Acoust Soc Am. 1985; 77: 1580-1588
        • Laukkanen A.-M.
        • Lindholm P.
        • Vilkman E.
        • Haatja K.
        • Alku P.
        A physiological and acoustic study on voiced bilabial fricative /β:/ as a vocal exercise.
        J Voice. 1996; 10: 67-77
        • Hammarberg B.
        • Fritzell B.
        • Gauffin J.
        • Sundberg J.
        Acoustic and perceptual analysis of vocal dysfunction.
        J Phonet. 1986; 14: 533-547
        • Mendoza E.
        • Valencia N.
        • Munoz J.
        • Trujillo H.
        Differences in voice quality between men and women: use of the long-term-average spectrum (LTAS).
        J Voice. 1996; 10: 59-66
        • Štajner-Katušić S.
        • Horga D.
        • Krapinec S.
        The voice of polypoid vocal folds before and after surgery.
        in: Hewlett N. Kelly M.L. Windsor F. Investigations in Clinical Phonetics and Linguistics. Lawrence Erlbaum Association, Mahwah, NJ2002: 437-448
        • Weinberg B.
        • Horii Y.
        • Smith B.
        Long-time spectral and intensity characteristics of esophageal speech.
        J Acoust Soc Am. 1980; 67: 1781-1784
        • Hollien H.
        • Majewski W.
        Speaker identification by long-term spectra under normal and sitorted speech conditions.
        J Acoust Soc Am. 1977; 62: 975-980
        • Valencia N.N.
        • Mendoza L.E.
        • Mateo R.I.
        • Carbello G.G.
        High frequency components of normal and dysphonic voices.
        J Voice. 1994; 8: 157-162
        • Cutnell J.D.
        • Johnson K.W.
        4th ed. Wiley, New York1998 (p. 466)
        • Haskel S.
        • Sygoda D.
        Biology, a Contemporary Approach.
        Amsco, New York1996
        • Yumoto E.
        • Gould W.J.
        • Baer T.
        Harmonics to noise as an index of the degree of hoarseness.
        J Acoust Soc Am. 1982; 71: 1544-1550
        • Li K.P.
        • Hughes G.W.
        • House A.S.
        Correlation characteristics and dimensionality of speech spectra.
        J Acoust Soc Am. 1969; 46: 1019-1025
        • Lofquist A.
        • Manderson B.
        Long-time-average-spectra of speech and voice analysis.
        Folia Phoniatr. 1987; 39: 221-229
        • Gauffin J.
        • Sundberg J.
        Spectral characteristics of glottal and voice source.
        J Speech Hear Res. 1989; 32: 556-565
        • Nordenberg M.
        • Sundberg J.
        Effect on LTAS of vocal loudness variation.
        Logop Phoniatr Vocol. 2004; 29: 183-191
        • Hurme P.
        Auto-monitored speech level and average speech spectrum.
        Pap. Speech Res. Univ Jyvaskyla. 1980; 2: 121-127
        • Monsen R.B.
        • Engebretson A.M.
        Study of variations in male and female glottal wave.
        J Acoust Soc Am. 1977; 62: 961-993
        • Van den Berg J.W.
        Sound production in isolated human larynges.
        Ann N Y Acad Sci. 1968; 155: 18-27
      2. Baer T. Investigation of Phonation Using Excised Larynxes [doctoral dissertation]. Cambridge, MA: MIT; 1975.

        • Tang J.
        • Stathopoulos E.T.
        Vocal efficiency as a function of vocal intensity: a study of children, women and men.
        J Acoust Soc Am. 1995; 97: 1885-1892
        • McAllister A.
        • Sederholm E.
        • Sundberg J.
        • Gramming P.
        Relations between voice range profiles and physiological and perceptual voice characteristics in ten-year old children.
        J Voice. 1994; 8: 230-239
        • Sundberg J.
        • Ternstrom S.
        • Perkins W.H.
        • Gramming P.
        LTAS average spectrum analysis of phonatory effects of voice and filtered auditory feedback.
        J Phonetics. 1988; 16: 203-219
        • Laukkanen A.M.
        • Syrja T.
        • Laitala M.
        • Leino T.
        Effects of two-month vocal exercising with and without spectral biofeedback on student actor's voice.
        Logop Phoniatr Vocal. 2004; 29: 66-76
        • Baken R.J.
        • Orlikoff R.F.
        Voice measurement: is more better?.
        Logop Phoniatr Vocol. 1997; 22: 147-151
        • Kreiman J.
        • Gerratt B.R.
        Sources of listener disagreement in voice quality.
        J Acoust Soc Am. 2000; 108: 1867-1876
        • Sundberg J.
        • Gauffin J.
        Amplitude of the voice source fundamental and the intelligibility of super pitch vowels.
        J Res Singing. 1983; 7: 1-5
        • Stathopoulos E.T.
        A review of the development of the child voice: an anatomical and functional perspective.
        in: White P. Child Voice. KTH Voice Research Centre, Stockholm2000: 1-12
        • Stathopoulos E.T.
        • Sapienza C.M.
        Developmental changes in laryngeal and respiratory function with variations in sound pressure level.
        J Speech Lang Hear Res. 1997; 40: 595-614
        • Hirano M.
        • Bless D.M.
        Videostroboscopic Examination of the Larynx.
        Singular, San Diego1993
        • Halle M.
        • Hughes G.W.
        • Radley J.-P.A.
        Acoustic properties of stop consonants.
        J Acoust Soc Am. 1956; 28: 303-305
        • Nissen S.L.
        • Fox R.A.
        Acoustic and spectral characteristics of young children's fricative productions: a developmental perspective.
        J Acoust Soc Am. 2005; 118: 2570-2578
        • Polgar G.
        • Weng T.
        The functional development of the respiratory system: from the period of gestation to adulthood.
        Am Rev Respir Dis. 1979; 120: 625-695
        • Lee S.
        • Potaminos A.
        • Narayanam S.
        Acoustics of children's speech: developmental changes of temporal and spectral parameters.
        J Acoust Soc Am. 1999; 105: 1455-1466
        • Kahane J.L.
        A morphological study of human prepubertal and pubertal larynx.
        Am J Anat. 1978; 151: 11-20
        • Sapienza C.M.
        • Hoffman B.
        Documentation of clinical features.
        in: White P.J. Child Voice. KTH, 2000: 105-128
        • Titze I.R.
        Principles of Voice Production.
        Prentice-Hall Inc, Englewood Cliffs, NJ1994
        • Abberton E.
        Aspects of voice quality in women.
        2006 (Available at:) (Last accessed January 7, 2007)
        • Sodersten M.
        • Hertegard S.
        • Hammarberg B.
        Glottal closure, transglottal airflow and voice quality in healthy middle-aged women.
        J Voice. 1995; 9: 182-197
        • Fant G.
        Glottal source and excitation analysis.
        Quart Prog Stat Rep. KTH. 1979; 1: 85
        • Shirastav R.
        • Sapienza C.M.
        Objective measures of breathy voice quality obtained using an auditory model.
        J Acoust Soc Am. 2003; 114: 2217-2224
        • Fritzell B.
        • Hammaberg B.
        • Gauffin J.
        • Karlson I.
        • Sundberg J.
        Breathiness and insufficient vocal fold closure.
        J Phonet. 1986; 14: 549-559
        • Sodersten M.
        • Lindestad P.-A.
        Glottal closure and perceived breathiness during phonation in normally speaking subjects.
        J Speech Hear Res. 1990; 33: 601-611
        • Shoji K.
        • Regenbogen W.
        • Vu J.D.
        • Blaugrund S.M.
        High frequency power ratio of breathy voice.
        Laryngoscope. 1992; 102: 267-271
        • Pabon P.
        • McAllister A.
        • Sederholm E.
        • Sundberg J.
        Dynamics and voice quality information in the computer phonetograms of children's voices.
        in: White P. Child Voice. KTH, 2000: 86-100
      3. De Krom G. Spectral correlates of breathiness and roughness for different types of voice fragments. Proceedings of International Conference on Spoken Language and Processing, Yokohama; 1994, pp. 1471–1474.

        • McGowan R.S.
        • Nittrouer S.
        • McGowan R.S.
        • Nittrouer S.
        Differences in fricative production between children and adults: evidence from an acoustic analysis of /sh/ and /s/.
        J Acoust Soc Am. 1988; 83: 229-236
        • Huber J.E.
        • Stathopoulos E.T.
        • Curione G.M.
        • Ash T.A.
        • Johnson K.
        Formants of children, women, and men: the effects of vocal intensity variation.
        J Acost Soc Am. 1999; 106: 1532-1542
        • Sulter A.M.
        • Albers F.W.J.
        Effects of frequency and intensity on glottal closure in normal subjects.
        Clin Otolaryngol. 1996; 21: 324-327
        • Schneider B.
        • Bigenzahn W.
        Influence of glottal closure configuration on vocal efficiency in young normal-speaking women.
        J Voice. 2003; 17: 468-480
        • Woods N.
        • College L.
        It's not what she says, it's the way that she says it: the influence of speaker sex on pitch and intonational patterns.
        Res Speech Rep Indiana Univ. 1992; 18 ([progress report]): 84-95
        • Whiteside S.P.
        • Hodgson C.
        • Tapster C.
        Vocal characteristics in pre-adolescent children: a longitudinal study.
        Logop Pediatr Vocol. 2002; 27: 12-20