The position of a speaker's pitch range conveys important information about the structure of the discourse. In this study we extract the pitch range of a speech database and compare the results with a register description of global prominence. The automatic extraction of the pitch range uses a parametric description of pitch accents and boundaries. We focused on the analysis of the pitch range properties during a sub-topic change, and found that the phonetic properties extracted from a database confirmed the predictions of the phonological model of global prominence: In phrases introducing a sub-topic, the lower margin is found to be at an average level, whereas the upper margin is clearly raised (extra-high register). In messages concluding a sub-topic, the pitch range is compressed and at a low level (low-compressed register).