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190 Chapter 11

Table 11.3
Default DECtalk synthesizer settings for Kismet’s voice (see the DECtalk Software Reference Guide). Section 11.3
describes the equations for altering these values to produce Kismet’s expressive speech.

DECtalk Synthesizer Setting Unit Neutral Setting Min Setting Max Setting
average-pitch Hz 306 260 350
assertiveness % 65 0 100
baseline-fall Hz 0 0 40
breathiness dB 47 40 55
comma-pause ms 160 −20 800
gain-of-frication dB 72 60 80
gain-of-aspiration dB 70 0 75
gain-of-voicing dB 55 65 68
hat-rise Hz 20 0 80
laryngealization % 0 0 10
loudness dB 65 60 70
lax-breathiness % 75 100 0
period-pause ms 640 −275 800
pitch-range % 210 50 250
quickness % 50 0 100
speech-rate wpm 180 75 300
richness % 40 0 100
smoothness % 5 0 100
stress-rise Hz 22 0 80

Pitch Parameters

The following six parameters influence the pitch contour of the spoken utterance. The pitch
contour is the trajectory of the fundamental frequency, f 0 , over time.

Accent Shape Modifies the shape of the pitch contour for any pitch accented word by
•
varying the rate of f 0 change about that word. A high accent shape corresponds to speaker
agitation where there is a high peak f 0 and a steep rising and falling pitch contour slope.
This parameter has a substantial contribution to DECtalk’s stress-rise setting, which
regulates the f 0 magnitude of pitch-accented words.

• Average Pitch Quantifies how high or low the speaker appears to be speaking relative to
their normal speech. It is the average f 0 value of the pitch contour. It varies directly with
DECtalk’s average-pitch.

• Contour Slope Describes the general direction of the pitch contour, which can be char-
acterized as rising, falling, or level. It contributes to two DECtalk settings. It has a small
contribution to the assertiveness setting, and varies inversely with the baseline-fall
setting.

• Final Lowering Refers to the amount that the pitch contour falls at the end of an utterance.
In general, an utterance will sound emphatic with a strong final lowering, and tentative if