Anand, once again I totally agree with everything you said in your post to Roy. I also have listened to the Summa, Abbey and Nathan, and your remarks about the Abbey and Nathan with respect to the differences and prices are spot on. Also on the dip at 0 degrees, I took my Abbey12As back over to Earls place so he could photo them for his website and so he could run frequency sweeps on both speakers after a month of use and "break in". It was very interesting watching Earl do the sweeps and you can actually see the on axis dip disappear in the measurements as the measurements are taken. He measures starting from 0 degrees at 16 degree intervals to 180 degrees. You can see the dip begin to lessen at 16 degrees and is almost gone at 32 degrees then at 48 degrees is completely gone. I was very impressed with Earls procedure for measuring the speakers and I learned a few things too on how to perform the measurements and what they mean. He also measured the two speakers output compared to each other and they were within less than 1/2 of 1dB of each other which was as low as the measurement program would measure in the mode he was testing in, so needless to say I am very impressed with the science behind as well as Earls attention to detail with the way he designs and manufactures his speakers.
Dan