Drawing melodies: evaluation of chironomic singing synthesis

Cantor Digitalis, a real-time formant synthesizer controlled by a graphic tablet and a stylus, is used for assessment of melodic precision and accuracy in singing synthesis. Melodic accuracy and precision are measured in three experiments for groups of 20 and 28 subjects. The task of the subjects is to sing musical intervals and short melodies, at various tempi, using chironomy (hand-controlled singing), mute chironomy (without audio feedback), and their own voices. The results show the high accuracy and precision obtained by all the subjects for chironomic control of singing synthesis. Some subjects performed significantly better in chironomic singing compared to natural singing, although other subjects showed comparable proficiency. For the chironomic condition, mean note accuracy is less than 12 cents and mean interval accuracy is less than 25 cents for all the subjects. Comparing chironomy and mute chironomy shows that the skills used for writing and drawing are used for chironomic singing, but that the audio feedback helps in interval accuracy. Analysis of blind chironomy (without visual reference) indicates that a visual feedback helps greatly in both note and interval accuracy and precision. This study demonstrates the capabilities of chironomy as a precise and accurate mean for controlling singing synthesis.