Incorrect Bark scale inversion

[scottlawsonbc]

In Bark.py there are two functions for converting between Hz and Bark units:

    def hz2bark(self, f):
        #       HZ2BARK         Converts frequencies Hertz (Hz) to Bark
        #
        z = 6 * np.arcsinh(f/600)
        return z
    
    
    def bark2hz(self, z):
        #       BARK2HZ         Converts frequencies Bark to Hertz (HZ)
        #
        f = 650*np.sinh(z/7)
        return f

These functions are not inverses of each other.

If we assume that hz2bark(f) is correct, then the correct inverse is f = 600*np.sinh(z/6), not f = 650*np.sinh(z/7).

The difference between the correct and incorrect version is shown below