Research Committee | Previous Projects
Influence of loudness variations on forensic fundamental frequency statistics
Michael Jessen, Bundeskriminalamt Wiesbaden, Department of Speaker Identification and Tape Analysis
The research project is based on a corpus of 100 male speakers of German who produced semi-spontaneous and read speech both under a baseline condition and under a Lombard condition, where 80 dB white noise was presented to the subjects, stimulating an increase in loudness relative to the baseline condition. The goal of the project is to derive from these signals global statistics of fundamental frequency, in particular mean f0 and f0 standard deviation and to observe the effect on these f0 measures induced by the change from normal to loud voice. Two issues in particular which will guide the statistical evaluation are:
- to what extent the increase in mean f0, which based on the literature is expected to occur in loud relative to normal speech, differs in magnitude between different speakers;
- if increased loudness leads to an increase in f0 standard deviation, as claimed by some authors, or whether f0 standard deviation stays roughly the same, as claimed by others.
Knowledge of these effects of loudness on f0 is important in forensic phonetic casework, where variations and mismatches in vocal effort are commonplace.