Measuring voice under teachers' working circumstances: F0 and perturbation features in maximally sustained phonation.

This study is part of a larger project, the aim of which is to develop a method for collecting voice data in working places. In this part, maximally sustained phonation was studied to assess its stability in this kind of uncontrolled circumstances. The subjects were 11 female schoolteachers. Different portions of a sustained /a/ and two consecutively produced samples were measured. The acoustic variables measured were fundamental frequency (F0), jitter and shimmer. The results showed that two consecutively produced phonations were quite similar, but the place of the sample within the sustained vowel had a very small but statistically significant effect on the values of F0 and shimmer. Jitter varied quite a lot, and could perhaps be considered to be dependent on the recording circumstances.