[The acoustic changes of the voice in the singing boys during the permutation period]

The present study was based on the assumption that the determination of the fundamental frequency (Fo) of the speech by means of computer-assisted acoustic analysis makes it possible to detect the onset of vocal mutation in the singing boys. A total of 30 singing boys were available for the examination. They were allocated to two groups. Group 1 was comprised of 15 boys at the age between 11 years 10 months and 12 years 4 months. Group 2 consisted of 15 boys aged between 12 years 10 months and 13 years 2 months. All the participants of the study underwent an acoustic test in combination with indirect laryngoscopy. It was shown that fundamental frequency of the speech in the boys of group 2 was significantly lower than in group 1. The difference amounted to two half-tones and could be regarded as the onset of vocal pre-mutation. It is concluded that the acoustic analysis of the speech should be employed to determine the time of vocal pre-mutation in the singing boys. The singing teachers can use this method all by themselves.