I went to a performance of the Hutchins Consort last night.
http://www.hutchinsconsort.org/
They play the full set of New Violin family instruments. The Contrabass Violin, deepest and largest of the family, has a massive low end. It was somewhat reminiscent of a pipe organ although not as powerful, obviously. It has exceptional projection.
It really was beautiful to hear the whole family of violins, eight in all, with the same sonority. I think it would be amazing to have an orchestra fully using this family of instruments.
Jim