  In this paper we review and refine a technique of Rioul to determine the
H\"older regularity of a large class of symmetric subdivision schemes from the
spectral radius of a single matrix. These schemes include those of Dubuc and
Deslauriers, their dual versions, and more generally all the pseudo-spline and
dual pseudo-spline schemes. We also derive various comparisons between their
regularities using the Fourier transform. In particular we show that the
regularity of the Dubuc-Deslauriers family increases with the size of the mask.
