These ceiling speaker reviews are interesting, but we just don't know enough about what measurements to aim for....and as they are such an unknown I think they're best to be avoided unless you don't have other options. But it'll be interesting to see what Amir comes up with re some other ceiling speaker measurements along with subjective listening, although I think subjective listening should be done in correct orientation - speaker above and listening subject at correct angled position under the speaker. The reason I think this is important is because HRTF's will be different for different incident angles (above & below subject will be different). Additionally, it might be interesting to add the difference between a "ceiling HRTF" and a "normal horizontal floor HRTF", add that difference to the spinorama to see if it fills in the large dip in the frequency response 1kH-3kHz.