The sound is absolutely incredible - it's difficult to distinguish from cello. On top of that - it can play polyphony because of the keyboard.
Da Vinci never saw this instrument completed but after 500 year's of this invention Polish concert pianist Slawomir Zubrzycki made it himself. It took 5000 hours in 3 years for him to do it.
Read the article and see the video
You will never believe what you are hearing until you see it...