The modern Bb trumpet is not a trumpet… The real Bb trumpet, in fact, is and always has been the Eb contra-alto trumpet whose useable range is identical to the Bb cornet. @
Torricelli’s trumpet is obviously not a ‘real’ trumpet, it is a 2D surface which is described by the equation x2(y2+z2)-1 = 0, x belongs to [1,∞) and can be formed by rotating the curve xy=1 around the x axis by 2π. @