This directly contradicts Lipsh!tz:
Harwood, H. "Audibility of phase effects in loudspeakers." Wireless World, January 1976, pp.30-32.
User wimms at diyaudio also criticizes Lipsh!tz:
http://www.diyaudio.com/forums/showt...853#post518853
However, the following shows that some localization cues are monaural:
"Temporal Localization Cues and Their Role in Auditory Perception." 95th AES Conference, Preprint #3798
Although phase cues between ears are used for localization, some have argued that phase distortion identical to both channels is not perceptible. However, the above article doesn't say monaural localization cues are only amplitude dependent, so I it leaves the possibility that monaural phase cues matter for localization.