From the musician's point of view, reeds considered as identical by the manufacturer (same cut, same strength and same brand) may exhibit large perceptual difference in terms of musical qualities. Past studies, carried out with clarinetists or saxophonists, have revealed that the reeds were mainly differentiated on the basis of their "ease of playing" which appears as the main perceptual descriptor of reed quality. This descriptor proved to be correlated with the reed stiffness measured at its tip in either static or dynamic conditions. The current study aims at discovering if other perceptual descriptors can be used to differentiate between reeds that would obtain similar "ease of playing" assessments (i.e. that exhibit the same stiffness). Firstly, the reeds are sorted on the basis of stiffness measurements carried out at the reed tip by using an artificial musician. Secondly, reeds of equivalent stiffness are selected for perceptual assessment by professional clarinet players. As this selection process might result in subtle differences between reeds, the musicians are asked to differentiate between them by using a comparison test. In addition to this perceptual assessment, the subjects are asked to verbally describe their criteria for reed differentiation.