it's very very cool, but i'm gonna be honest, i just want to pick it apart. as a string musician of many years, it sounds to me like a shitty viola that can play more notes at once. no offense to ol' da vinci.. but i think it could be improved. i say this because a huge amount of the skill in playing a bowed instrument is controlling changes of bow direction and the beginnings of bowings. if you aren't skilled enough, your bow transitions and beginnings are jarring, rather than the liquid sound of a skilled string player.

the reason this machine sounds so bad to me is that its design removes a lot of the variables that are important for nuanced tone quality. bowed instruments simply have a lot more variables involved than struck instruments such as pianos or harpsichords. in a violin, viola, or cello, the bow has uneven tension along its length, allowing for many different articulations - it also means that when you start the bowstroke at the top or bottom of the bow, the hair tension is higher at those points. so, given an even downward bow pressure, the start of the stroke at either end of the bow has less friction and therefore less volume than the higher-friction middle, creating a naturally smooth attack as you draw the bow. this says nothing of the ability of the musician to change the bow pressure along the bowstroke, another variable.

the viola organista, on the other hand, presses a metal string to a rotating bow of even tension with constant force. since the string and bow are both evenly tense along their length in this design, there is no possibility of controlling the attack and release of a note, giving a binary, on/off, jerky sound with less continuity between notes.

but theres even more to this. a traditional bowed instrument not only has uneven tension in the X-axis (the bow axis), but also has uneven tension in the string axis. violins, violas, and cellos all have a bridge. the bridge not only transmits the vibration to the soundboard, it creates a tension differential just like the bow. but the resonant property of the bridge means that the string tension corresponds to resonance. the closer you bow to the bridge, the louder, fuller, and more resonant the tone. but also, the closer you bow to the bridge, the less the tension of the string is affected by the downward bow pressure (since the string is higher tension). so, bowing closer to the bridge, the resonance is large and doesn't change very much with differing bow pressure, while bowing further away from the bridge, the resonance is relatively less but is also affected more by bow pressure (since the string is less tense, so increased downward pressure by the bow pushes the string down and raises its tension).

the point of all this shit is to say that traditional bowed string instruments are incredibly complex dynamic systems and a lot of their dynamism has been thrown away in this design, yielding something that offers less tonal control with no tangible benefits beyond being able to bow more strings at once. sorry da vinci.