[The influence of vowel and sound intensity on the results of voice acoustic formant detection was analyzed].

<b>Objective:</b>This study aims to explore the influence of vowels and sound intensity on formant, so as to provide reference for the selection of sound samples and vocal methods in acoustic detection. <b>Methods:</b>Thirty-eight healthy subjects, 19 male and 19 female, aged 19-24 years old were recruited. The formants of different vowels（/a/, //, /i/ and /u/） and different sound intensities（lowest sound, comfort sound, highest true sound and highest falsetto sound） were analyzed, and pairings were compared between groups with significant differences. <b>Results:</b>①The vowels /a/ and // in the first formant were larger than /i/ and /u/, and /i/ was the largest in the second formant. The minimum value of the first formant is the lowest sound of /i/ and the maximum is the highest sound of /a/. ②In the first formant, the chest sound area increases with the increase of sound intensity, while the second formant enters the highest falsetto and decreases significantly. <b>Conclusion:</b>Different vowels and sound intensity have different distribution of formant, that is, vowel and sound intensity have different degree of influence on formant. According to the extreme value of the first formant, the maximum normal range is determined initially, which is helpful to improve the acoustic detection.