And some contrary views by Ted Jordan
"It would seem at first logical to design loudspeaker systems to have the widest possible angle of distribution, in fact the omni-directional design would seem ideal - actually this is quite untrue. It is now generally recognised that omni-directional systems have never been popular, although the reasons have not been appreciated, and these are:
A random radiation of sound in all directions results in an excessive ratio of reflected to direct sound and the subjective quality tends to be thin and very dependent upon room acoustics.
It is not possible for an omni-directional system to provide satisfactory stereophonic performance."
"It would seem at first logical to design loudspeaker systems to have the widest possible angle of distribution, in fact the omni-directional design would seem ideal - actually this is quite untrue. It is now generally recognised that omni-directional systems have never been popular, although the reasons have not been appreciated, and these are:
A random radiation of sound in all directions results in an excessive ratio of reflected to direct sound and the subjective quality tends to be thin and very dependent upon room acoustics.
It is not possible for an omni-directional system to provide satisfactory stereophonic performance."