Spatial localization of sound is often described as unconscious evaluation of cues given by the interaural time difference (ITD) and the spectral information of the sound that reaches the two ears. Our present knowledge suggests the hypothesis that the ITD roughly determines the cone of the perceived position (i.e. the azimuth in a polar coordinate system with left-right poles), whereas the spectral information determines the position on the cone (i.e. the elevation in the same coordinate system). This hypothesis was evaluated in a series of listening tests, where the two cues were manipulated independently in HRTFs used for binaural synthesis. The ITD seems to be dominant for localization in the horizontal plane even when the spectral information is severely degraded.