Figure 1.

Examples of Lx signals for loud, normal, and soft speech from speaker M01 at midvowel in stressed and accented position. Data printed as thin lines correspond to the first derivative of the Lx pulses (bold lines). In the upper panel landmarks are denoted by numbers: (1) onset of closing at maximum of the first derivative, (2) maximum contact, (3) moment of glottal opening, determined by a 3∕7 threshold, and (4) next glottal closing. The length of the arrows corresponds to the open glottis interval.