The relation between speech production and perception parameters is investigated for synthetic stationary vowels. A perceptual distance measure, based on the distance between excitation patterns, is used to quantify and model the perceptual relevance of variations to glottal-pulse parameters. The parameters that are studied are the R parameters of the well-known Liljencrants–Fant (LF) model. An approximation of the perceptual distance measure was used to quantify the perceptual effects of the R parameters. The data used in this paper consist of 33 R-parameter vectors which all have been measured from real voices and have been taken from the literature. The 33 points in the R-parameter space are found to lie near a trajectory when ordered as function of a perceptual parameter, which was derived from the perceptual distance measure. This ordering seems to be largely independent of other speech parameters, such as F0 values, level and of parameters of the vocal tract filters. Finally, it is demonstrated that the perceptual parameter has a close relation to the production parameter Rd, described in [Fant, G., 1995. The LF-model revisited. Transformations and frequency domain analysis.