• Speech Sciences
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• v.10 no.2
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• pp.145-157
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• 2003

Vowels are classified by the shapes of vocal tract. These shapes form constriction points along the tract, which have an influence on such vocal tract resonance as F1, F2, F3, and so on. The formant frequency is influenced by aperture and placement of tongue and the intensity is influenced by air pressure of subglottis. The object of this study compares to characterize the spectral outputs of oral and nasal spectra for the formant frequencies and intensity of Korean oral vowels. Subjects consisted of 20 normal persons (10 male and 10 female) without laryngeal pathology. The speech sample included /a/, /e/, /i/, /o/, /u/ of Korean oral vowels. The spectrum of each vowel was analysed by Nasal View and Real Analysis Program using Dr. Speech. The result showed that nasal intensity is decreased manifestly from F1 to F2. But oral intensity and Intensity is decreased little bit from F1 to F2. The most of values of nasal formant frequency is similarity oral formant frequency and Formant frequency or little bit smaller.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.1
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• pp.27-31
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• 1998

Nasal sounds include nasalized vowels and consonants. Nasal cavity is important for the acoustics of nasal sounds. Evaluating the effects of site-specific nasal obstruction on nasal sound will help us to understand the importance of nasal geometry for the nasal sound and to foretell voice change after nasal surgery This study was designed to analyze the change of nasality and formant characteristics of nasal sound by obstructing different sites around the ostiomeatal unit(OMU). Ten adult male and female volunteers participated. The nasal formants and bandwidths of nasal consonant /n/ were checked in various conditions of nasal obstruction. The nasalance of rabbit, baby, and mama passages were compared in each conditions. Nasalance of all passages decreased when anterior portion of OMU was obstructed. Center frequency of first nasal formant(NF1) of /n/ has decreased in the order of anterior, inferior obstruction. The bandwidth of NF1 decreased in female with anterior obstruction. Anterior portion of OMU is most critical to the change of nasality and acoustics of nasal consonant. When anterior portion of OMU is obstructed, the shift of NF1 to a lower frequency and the narrowing of NF1 bandwidth are the major acoustic changes of nasal consonant /n/.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.12 no.1
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• pp.34-38
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• 2001

Background and Objectives : With the development of computerized systems, an objective evaluation methods of nasal speech and nasal geometry have become readily available by means of a simple, noninvasive technique. In this study, we assessed the nasality, nasal formant, nasal volume and nasal area in patients with hypertrophic rhinitis before and after turbinate surgery. Material and Method : With the nasometer, we measured nasalance, which reflects the ratio of acoustic energy output of nasal sounds from the nasal and oral cavities. With CSL 4300B, we measured nasal formants. We used acoustic rhinometer to measure nasal area and nasal volume. Postoperative changes of above factors were compared with preoperative values. Paired t-test and Pearson's correlation were used for statistical analysis. Results : The first nasal formant frequency, nasalance scores of three passages(baby, mamma and rabbit passages), minimal cross sectional area(MCA) of narrow side, nasal volume of narrow side and nasal volume of wide side had increased significantly after turbinate surgery (p <0.05). The MCA and nasal volume of narrow side and MCA of wide side showed significant correlation with nasalance score of rabbit passage and baby passage showed significant correlation with nasal volume of narrow side(p<0.05). Conclusion : There were significant increases in nasalance scores, first nasal formant frequency, MCA and nasal volume after turbinate surgery. Thus, we must consider the possibility of voice changes postoperatively in professional voice users.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.18 no.1
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• pp.33-38
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• 2007

Background and Objectives: It has been suggested that tonsillectomy possibly causes changes of voice because the morphology of the vocal tract is altered. This may cause serious problems for professional voice users. Materials and Method: Subjects were 26 patients. The oral and nasal sound spectrum of oral vowel /a/, /e/ and /i/ were measured before and after tonsillectomy. The formant frequencies and intensities for oral and nasal spectra were compared. The nasality and fundamental frequencies for oral vowel were measured. Results: The first formant frequencies for oral spectra of all vowels were not changed after surgery, but the second formant frequencies were increased significantly after surgery in the vowel /e/ and /i/. The first and second formant intensities for oral spectra were increased significantly after surgery in the all vowels. The first and second formant frequencies for nasal spectra of all vowels were not changed after surgery, but their intensities for nasal spectra were increased after surgery. The nasalities for oral vowel were not changed after surgery. Conclusion : Tonsillectomy appeared to change the spectral features of oral and nasal components of oral vowel, especially spectral intensities.

• MALSORI
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• no.31_32
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• pp.9-22
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• 1996

This study aims to describe the acoustic characteristics of Korean nasal sounds making use of the notion of pole and zero. In case of [m], the 1st and 4th formant almost remains as the original shape respectively, on the contrary, the 2nd and 3rd formant were observed as a variable cluster together. Alveolar [n] shows that the 3rd and 4th formant make a variable cluster with their antiformant(zero), however, the 1st and 2nd formant keep the static shape of their on. Velar [$\eta$] has 4 formants below 2900 Hz and the 3rd and 4th formant constitute a variable cluster together as does the case [n]. With respect to the energy distribution in case of [n] and [$\eta$], the energy value diminishes from Fl up to F3 continuously but augments in F4. The [m] shows that in the region of Fl-F2 does the energy fall down and rise from F3 to above.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.8 no.2
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• pp.161-165
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• 1997

Background : The rhinomanometry and acoustic rhinometry can assess e nasal passage dynamically and statically Recently, analytic methods such as nasometer and sound spectrogram are gaining wide attention to evaluate the nasality objectively. Objectives : firstly to determine if ere was a relationship between the new methods and nasal airway resistance, and secondly to establish if the measurement of nasalance and sound spectrum could be used as an alternative to rhinomanometry and acoustic rhinometry. Materials and Methods : Thirty two patients who underwent either septoplasty and turbinectomy for nasal obstruction were studied. And their ages ranged form 15 to 45 years, with an average of 26.1 years. The rhinomanometry, nasometer, sound spectrogram were performed at preoperative and postoperative 4 weeks day. Results : After operation, subjective symptoms and rhinomanometric results were significantly improved but nasalance and slope of nana, mama and mamma passage had not meningful change. The significnat changes were noted in nasalance and first nasal formant frequency of nasal consonant of velum(angang). Conclusion : Nasometer and sound spectrogram had a limitation for the measure of nasal patency.

• Proceedings of the KSPS conference
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• 2003.10a
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• pp.55-58
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• 2003

The purpose of this paper was to analyze the effects of nasalization on vowels. Ten males and 7 females produced 5 vowels (/a/, /e/, /i/, /o/, /u/) in conditions: normal and nasalized. In this study we compared normal vowels' formant with nasalized vowels' and examined nasal-formant in the nasalized vowels. The results was as follows: First, there was a significant difference between normal vowels and nasalized in terms of F1 and F2. Second, the nasal formants were observed in nasalized vowels more frequently in females than males. Third, N1 appeared to influence F1 of vowels whereas N2 seemed to have an impact on F2 and/or F3.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.1
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• pp.32-37
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• 1998

Tonsillectomy is the one of operation that is performed the most commonly in otolaryngology field. Many changes that include range of voice, tone, voice quality and resonance were made by tonsillectomy. Sometimes, any patients taken tonsillectomy has suffer from these voice problem after tonsillectomy. However there are less study for these problems until now. Then, we studied to find the anatomical findings that affected the voice quality when tonsillectomy was performed. We evaluated the voice in 2 groups, one is the group showed the normal pharyngeal space by using the transnasal fiberscopy, the other is group showed medially bulging tonsil at pharyngeal cavity by using same method, with perceptual evaluation, nasalance score, nasality, oral formant and nasal formant. We used the computerized speech analysis system, the nasometer and the spectrogram in the CSL program. We could not find any differences in perceptual evaluation between two groups. But objective measures were provided. Nasalance score and nasality on the nasometric analysis were increased significantly and oral formant on the spectrogram was changed singnificantly after tonsillectomy in Group 2. Authors thought medially bulging tonsil in the pharynx is able to affect the voice quality after tonsillectomy when we evaluted through the nasal cavity by the using of fiberscopy and this evaluation would be important especially in singers.

• Journal of Biomedical Engineering Research
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• v.11 no.2
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• pp.283-288
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• 1990

As one of the main purpose of the physical management of cleft palate is to provide for the anatomic and physiologic requisites for speech, the speech must be as one of the criteria for determining when physical management has been achieved. But there is no objective methods to evaluate the speech of cleft palate patients. The authors tried to analyze the speech of adult cleft palate patients using sound spectrog raphy and compared with normal adults. The results were obtained as follows ; 1. In Vowels, cleft palate patients of both sexes showed reduction of frequency of the first and second formant as compared to normal. There was minimal difference in front vowels (i, e, ae) 2. In consonants, cleft palate patients showed reduction of frequency of the first formant in both sexes but reduction of frequency of the second formant was noticed only in fe- male patients. 3. There was no statistical difference in sound spectrograph between plosive, fricative, africative, nasal, and glide consonants.

• The Journal of the Acoustical Society of Korea
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• v.31 no.6
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• pp.353-358
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• 2012

This paper describes acoustic phonetic parameters for detecting nasal place in a knowledge-based speech recognition system. Initial acoustic phonetic parameters are selected by studying nasal production mechanisms which are radiation of the sound through the nasal cavity. Nasals are produced with differing articulatory configuration which can be classified by measuring acoustic phonetic parameters such as band energy ratio, band energy differences, formants and formant differences. These acoustic phonetic parameters were tested in a classification experiment among labial nasal, alveolar nasal and velar nasal. An overall classification rate of 57.5% is obtained using the proposed acoustic phonetic parameters on the TIMIT database.