The contribution of high‐frequency and of low‐frequency spectral information to the detection of temporal variability or “jitter” of auditory pulse trains was examined. Pulse trains were subjected to low‐pass, to bandpass, and to high‐pass filtering. Jitter discrimination for low‐frequency pulse trains is substantially poorer than for high‐frequency pulse trains. The reason is not that the low spectral frequencies within low‐frequency pulse trains interfere with jitter discrimination, nor that low‐frequency pulse trains contain insufficient high‐frequency spectral information. Rather, it appears that the spacing between high‐frequency spectral components of low‐frequency pulse trains is too close to permit effective resolution.