The ability of observers to discriminate interaural differences in the (modulator) phase or modulation rate of amplitude‐modulated wide‐band noise signals was investigated using a 4AFC paradigm. Among the parameters studied were: modulator waveform; interaural coherency of the noise carriers; and modulation rate. The effect of bandpass filtering after modulation was also investigated. For the case of binaurally incoherent noise, discrimination performance for both phase and modulation rate differences deteriorated rapidly for modulation rates above about 300 Hz. This low‐pass behavior is typical of that found for various monaural phenomena associated with amplitude modulation (e.g., nonspectral pitch) and presumably reflects the ability of auditory systems to utilize information from the envelope of the modulation waveform. For binaurally coherent wide‐band noise, on the other hand, discrimination performance for phase and modulation rate differences were largely independent of (average) modulation rate. [Work supported by NIH.]