Despite a number of recent studies on the production of multiphonics in woodwinds, an exhaustive study on the perception of these sonorities is still missing. In this work we undertake a comparative study of saxophone multiphon- ics from the musical, perceptual and acoustical points of view. We propose four major classes based on the analysis of the musical attributes and playing techniques of a set of 118 alto saxophone multiphonics, spanning all the possible sonorities previously reported. Then, we perform a dissimi- larity rating experiment for all possible pairs of a subset of fifteen representative multiphonics. This experiment provides confidence in the suggested classification, since the four classes are segregated in a Multidimensional Scaling (MDS) representation. We also find two possible acoustical correlates of the perceptual dimensions: the spectral centroid (SC) and the modulation frequency (MF). Finally, this last representation is explored through morphing trajectories, which correspond to multiphonics that change the timbre and musical interval organization with fixed fingering