At one time it was felt that interaural differences of time could affect the localization only of low frequencies. Psychoacoustic support for this view came from observations with sinusoidal stimuli that showed a total insensitivity to interaural delays in tones above about 1.5 kHz. In recent years, however, it has become increasingly clear that listeners can detect interaural delay in signals of high‐frequency content, as long as the spectrum is complex. For example, performance can be excellent when the signal is a high‐frequency carrier that has been modulated in amplitude. The purpose of this paper is to discuss functional differences between simple and complex sounds, with an eye toward development of a model of binaural interaction that accounts for the responses to both. Toward this end, special attention will be paid to stimulus factors that differentiate the two classes. In the preceding paper, Yost compares the responses to interaural differences of time in the stimulus onset and in the waveform. That notion will be expanded here in a model which attributes a spectral role to onsets and which visualizes both individual peaks in the envelopes of high frequencies and the oscillations of low frequencies as successions of mini‐onsets.