Five perception experiments were conducted that investigated how the perceived prominence of F0 maxima in accented syllables in Dutch is affected by the variation of F0 minima that is supposed to relate to variation in global pitch range. The purpose of the first two experiments was to test the predictions of a model in which the reference line is directly given by an interpolation between observable F0 minima. The results showed that the model was inadequate, and confirmed earlier research suggesting that the reference line is calculated in a less direct way. The next three experiments investigated the role of the F0 of the unaccented portions of speech at the beginning ("onset") and at the end ("offset") of the contour, and show that only the (low) onset is used to calibrate the reference line. The results also suggest that longer onsets affect the abstract reference more than do shorter onsets.