The accuracy of subjects localizing low- and high-pass-filtered white noise was investigated in order to establish the frequency spectrum necessary for localization. The directions most often perceived by subjects localizing white noise coloured by high-pass, low-pass, bandpass, and bandstop filters were observed. Several artificial ears were then investigated for frequency response with different angles of median-plane incidence. It was found that sound spectra between 4 and 16 kHz are required for localization, and details of the cues involved in front, above, and behind localizations are given