If you would be more specific about which cabinet maybe we can help
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I am building some Omni Top 12's but thought that maybe if people who had installed top hats could post their measurments it could give others a good idea as to where they could install them. If all of the measurements are relatively close for the individual cabinets then, maybe, it could be added to the plans? Just a thought. I did figure for the 12's that the only place was what is shown in the plans. I do plan on building some 250's and may want to mount them, if it is possible of course. Thanks.
It's not the SPL output I worry about, it is the SPSL output!
You could always put the speakers on a table or bench (or just a plank of wood on the ground) and slowly, little by little, push them toward the edge. At some point, when the speaker wants to tip over, that's where the center of gravity is in that direction on that plane. Do it in both directions and where the two lines intersect is where a pole mount will be ideal as it will balance the box on the pole.