Hi Russ,
I'm not Gary, but I'd like to tell you about my 'mixed feelings' and my own conclusion on this matter. My first impression was that indeed the low frequencies' decay with distance is signicantly greater than mids' and highs'. This was in a open field with no fixed structures (wall, etc) to 'encapsulate' (I hope you understand me) the subwoofer. My first thought was that I maybe should get the second sub for outdoor venues. However I had experiences that contradict my first impression. I had the PAS in a sort of long gallery with walls and a wood ceiling around, projecting the sound to an open field. My clear impression is that the low freqs. were much more present in the overall sound at considerable distance. Of course this is not intrinsically achieved by the sound system itself but with the help of structures around. I have another job in the place I just described next saturday, and I'll shoot some pics, to help you understand the situation. My present conclusion is that the location of the subwoofer is extremely important to efficiently project low frequencies at long distances.

-- José.