Not sure but the Phase Linear andromeda was almost omni directional all the hi frequency drivers shot straight up into what looks like an upside down cone. The bass drivers face the floor, as according to some very highly respected speaker builders say that is the only way to really fire a low frequency driver. But the mid base drivers which their are two have no rear cabinets the backs are wide open, the midrange drivers two one forward, one rear facing.
I have a pair of them and a pair of the newer designed series III's which replace one of the hi frequency drivers with a forward facing audux soft dome.
I guess not truely omni directional but pretty close, and I can say, the series III's image very well because the mid forward firing speaker and the hi frequency audux presents a pretty detailed focal point. But the soundstage is great, and they do sound very good for a pair of 35 year old speakers. I consider them some very enjoyable listening speakers.
Unlike the Zenith's or other lesser designed speakers, these are in my opinion some very well designed and engineer speakers. They were not some cheaply made speakers for the masses.