Voks: Digital instruments for chironomic control of voice samples

•Voks is a family of digital instruments for real-time control and modification of voice signal samples, with the help of hand-driven interfaces.•Voks allows for high quality performative voice with applications to musical and poetic performances or speech laboratory experiments.•Applications in speech communication (e.g. to language learning, voice substitution and speech reeducation) are foreseen.•Voks methodology is based on control points for rhythm, and chironomic control for intonation.•The article contains a detailed theory, including the mathematical framework, comparative perceptual evaluation, video and audio examples. This paper presents Voks, a new family of digital instruments that allow for real-time control and modification of pre-recorded voice signal samples. An instrument based on Voks is made of Voks itself, the synthesis software and a given set of chironomic (hand-driven) interfaces. Rhythm can be accurately controlled thanks to a new methodology, based on syllabic control points. Timing can also be controlled with other methods, including scrubbing and playback speed variation. Pitch, vocal effort, voice tension, apparent vocal tract size, voicing ratio, aperiodicity ratio of the voice samples can be modified thanks to a real-time high-quality vocoder. Different forms of chironomic control of the vocal parameters are proposed. Pitch is controlled by continuous hand motions using a stylus on a surface (C-Voks) or a theremin (T-Voks). Other interfaces can be used as well. Syllabic rhythm is controlled using a biphasic button. Scrubbing, playback speed and timbre related parameters can be controlled using the theremin, control surfaces or continuous controllers like faders. In addition to realistic imitation of speaking or singing voices, other playing modes yield new interesting sounds. Voks participated in comparative perceptual evaluation of singing synthesis systems. It has been demonstrated in a live musical settings, using different control interfaces. In addition to musical or poetic performances, applications of performative vocal synthesis to language learning and speech reeducation are foreseen.