In a stereophonic broadcasting system, differences between the phase/frequency or amplitude/frequency characteristics of the left and right channels may result in unwanted displacements or dispersion of the sound images across the stage; interchannel phase differences, moreover, may impair the volume or quality of the compatible monophonic transmission. These effects have been subjetcively assessed and the resulting data used to derive limits for the permissible interchannel difference in phase/frequency and amplitude/frequency characteristics. The experiements were carried out as a contribution to the work of the European Broadcasting Union (EBU).