Figure 4: Low track activity (red boxes) produced by a speaker with ADSD, Pre-BT. Note: long duration of the sound [a] in “man” from the phrase “When a man looks…” This segment has a “zeroed” f0 track (< 80 Hz) where modal f0 was traceable, between red boxes, for only 18% of [a] in the word [man]. Intervals of zeroed f0 correspond to isolated glottal pulsing on the waveform (top) and vertical striations on the spectrogram (bottom). This was perceived as severely strained-strangled voice with reduced intensity and associated voice breaks.