In this research, some of audio signal properties have been studied according to the
speaker's vocal tract shape. A database of audio files has been recorded. These files belong
to 57 men whose age between 35 and 45. All speakers came from the same
academic and
social culture. Furthermore, they don't suffer from any problems in hearings and utterance.
The vowel database was created in perfect recording conditions. The spent time
needed for recording process was about five minutes for each speaker who said the Arabic
word " سألتمُونِيهَا " three times. That word is very rich of vowel letters. It composes of the
whole Arabic long vowel.
Based on the analysis study of the recorded audio signals, the relationship between
the formant frequencies and the length of speaker's vocal tract has been studied. The results
show an inverse proportion for the first three frequencies F1, f2, F3 and no clear
relationship for the two other frequencies F4, F5.
