Since a few years, after a lot of testing with different materials and also full wood versions, Cessaro uses now composite horns which are handmade and based on a two shell construction with a special polymer rubber filling in between (the inner and outer shell).What type of material is used in Cessaro horns?
It has the least sound of it's own, not (only) while knocking on it but while playing the full sound spectrum.
And no i don't have measurements to prove. (maybe/probably the manufacturer has)
No to be honest it is not hard. But yes it is heavy and you are right you don't feel any vibration.It is some kind of composite material. Very hard, heavy and inert. Put you hand on while playing you dont feel a thing no vibration. I hear some people commented that they are not as organic sounding as wood one. I think that is more brain and preference talking.