Jussi is a unique vocal synthesizer that creates the sound of a male voice using pure synthesis without relying on any samples. The instrument responds dynamically to how you play it, with formant shapes controlled by the velocity of each note. This means a soft keystroke produces a gentle 'oo' vowel sound, while a harder strike triggers a more aggressive 'aa' vocal tone. This expressive control allows musicians to explore vocal sounds in innovative ways, adding an organic and playful dimension to their compositions.

The synth features an ADSR envelope with specialized 'Turn-in' and 'Turn-out' settings, which influence pitch during the attack and release phases, adding expressive articulation to the vocals. It includes a voice character XY pad that adjusts the intensity and narrowness of the vocal tone, giving users flexibility in shaping the sound. Legato mode enables smooth transitions between notes and velocity levels, while Legato Hold mode allows polyphonic legato effects when using a sustain controller, expanding performance possibilities.

Further sound design options are available through a throat emulation XY pad that controls grain and tonality, simulating vocal tract characteristics for more realistic vocal textures. Additionally, the built-in reverb adds depth and space to the sound, enhancing its presence within a mix. Jussi stands out as an exciting instrument that blends expressive vocal synthesis with creative modulation capabilities, perfect for adding fresh vocal elements to a wide range of musical styles.