Formant frequency

We know fi om acoustic phonetics that typical formant values for an /ih/ vowel are 300Hz, 2200Hz, and 3000Hz. Formant bandwidths are harder to measure accurately, but less us assume a value of 250Hz for all three formants. Assuming a sampling frequency of Fs = 16000/7z, the following table shows how to calculate the poles from the formant frequencies and bandwidths. 

Formant Frequency (Hz) Bandwidth (Hz) r 0 (normalised angular frequency) pole... 

Figure 10.25 shows the pole-zero plot and fi equency response of the transfer function. From the plot, we can see that the formant frequencies do indeed appear at the approximately the desired locations. 

Poles have an easy to imderstand interpretation, and in many cases, formant frequency and bandwidth can be directly related to pole values. By suitable choice of pole, a frequency response with appropriate resonances can usually be constructed. 

Gender Identification by Using Fundamental and Formant Frequency... 

Keywords— Formant Frequency, Fundamental Frequency, Malay Vowel, Gender Identification in Children, Children Speech. 

One of the most important components of the human speech is formant frequency and has been studied in children and adults across different languages so far. As matter of the fact, formant frequencies make vowels identifiable for listener. Because of the different formants position in vowels of male and female, formant frequency can be used in gender identification especially in the first three formant frequencies of vowels [1, 2]. A need to look into the Malay children s formant and fundamental frequencies of Malay vowels, is obvious and the effect of them on the matter of gender identification is considerable. The aim of the present study is to find any systematic differences related to gender in fundamental and formant frequency values of vowel /a/ which is produced by Malay children between 7 to 12 years old. 

Peterson and Barney [1] studied the fundamental frequency and the first three formant frequencies of ten American English vowels. Then the study was extended by Hil-lenbrand et al. [2]. They found numerous differences in terms of average frequencies of FI and F2 compared with the study of Peterson and Barney. But in both of these studies, the age and sex of children were not specified. 

Fundamental frequency and first four formant frequency values were extracted and determined for each subject by using the Praat software [10], Standard formant settings were used 5500 Hz for maximum formant frequency, 5 numbers of formants, 25 ms for the window length and a dynamic range of 30 dB. 

Other previous studies confirm that the F2 values were the best gender identification factor in formant frequency in all age groups due to lower amount in standard deviation. [3, 5, 11, 12], They also mentioned that the FO values were a poor factor in this matter. In contrast Hasek et al [8] found the differences between two genders by using FO values for 7 to 10 years old children. 

According to the previous studies, K-factors or F-scaling were also used to describe the relationship between the formant frequency values of males and females [1, 3, 6, 7, and 13]. 

Table 2 illustrated the results of gender identification accuracy across the combination of two different fundamental and formant frequencies in different age groups. Based on the results of table 1, different combination of formant and fundamental frequencies were selected and calculated the accuracy of gender identification for all of them. According to Gelfer and Mikos [14] results, combination of the two set of cues improve the gender identification accuracy and it our results also showed. 

The study investigated the first four formant frequencies and fundamental frequency of sustained vowel /a/ in normal Malaysian Malay children between 7 to 12 and applied them for gender identifying. The results showed that the second formant frequency was the best and also fundamental frequency played a role in the matter of gender identification. The combination of FO and F2 also compared with other possible combination to get a good accuracy. The best accuracy belongs to the F2 and combination of FO and F2. 

Busby, P.A. Plant, G.E (1995) Formant frequency values of vowels produced by preadolescent boys and girls. J. Acoust. Soc.Am.91(4ty. 2603-2606... 

Gelfer, M. P., and Mikos, V. (2005) The relative contributions of speaking fundamental frequency and formant frequencies to gender identification based on isolated vowels. 1. Voice 19(4) 544-554. 

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