We, in other words men and women, naturally and instinctively locate the positions of any and all sounds that we hear. We have had a long time to evolve this skill and in earlier times it was crucial to whether we survived - or not. In fact it was so important and over so long a time that we now can t stop doing it, it is part of our nature. We know that we locate the position of sounds by interpreting both the amplitude and arrival times of sound reaching our two strategically placed ears. A good stereo recording can preserve these positional cues and even a poor one is unlikely to be entirely devoid of them, but phase distortion in loudspeakers alters these cues in such a way that the timing differences available to our ears no longer make perfect sense.
Effortless music is the whole point.
If all that sounds very seriously subtle, then please consider these results of a typical hi-fi loudspeaker with phase distortion trying to reproduce a square wave. The left photograph is of a good speaker with a good frequency response failing miserably to produce a square wave at the measuring microphone 6 feet away. All of the different frequency components present in a square wave do eventually get to the microphone, but with the arrival times altered enough so that the microphone sees nothing which resembles a square wave. With our loudspeaker, with the phase relationship preserved, the right photograph is obtained showing accurate reproduction. Practically all loudspeakers need more than one driver to adequately cover the entire audio spectrum from 20Hz to 20khz, hence the common acceptance of the terms two way or three way to describe how many different sections the audio spectrum is split into.