In this paper we are looking for a robust value of the spectral moments that does not change when a speaker varies his vocal effort from normal to loud speech. To do this we first calculate the first four spectral moments for normal and loud speech. Then we compare the results for each single phoneme. After this, we do a correlation analysis to check whether normal and loud speech are linked with each other linearly. The results of the investigations show that plosives and fricatives are robust to changes of vocal effort. Vowels and sonorants demonstrate significant differences in vocal effort.
Bibliographic reference. Gottsmann, Frederike / Harwardt, Corinna (2011): "Investigating robustness of spectral moments on normal- and high-effort speech", In INTERSPEECH-2011, 2937-2940.