Discussing the acoustic condition in auditoria is difficult due to two major shortcomings. Firstly the uncertainty of room acoustical measurement is still under investigation and secondly the present understanding of how sensitive listeners are to perceive differences in sound fields in auditoria appears incomplete. How these aspects are related to each other can easily be seen when the fluctuations of single number parameters (e.g. C80, LF, etc.) depending on the micro- phone position, as described by de Vries, are compared to just noticeable differences quoted in ISO 3382. Such findings would suggest that the perception of the sound fields in an auditorium varies already with minor changes of the listener position. Since it is common experience that such changes are not noticeable, the reason for this false reasoning needs to be analysed. A joint discussion of measurement uncertainties and perceptual aspects has the potential to clarify this aspect. In this project two topics are addressed in parallel. On the one hand the discussion of meas- urement uncertainty according to the framework of the “Guide to the expression of uncertainty in measurement” (GUM) will treat influence factors that have not been discussed in detail yet. On the other hand just noticeable difference for widely used room acoustic quantities will be determined on the basis of realistic presentations of real sound fields. Standard statistical methodologies to analyse the data from listening tests (such as constrained maximum-likelihood strategies) will be enhanced to include the statistical measurement uncertainty of the physical quantities (describing the stimuli). Based on these advances the determined difference limens have the potential to better reflect a listener’s sensitivity.