Hi Whart. Interesting thread. WOW.... from E-stats to Hi efficient horns? After reading a few posts here I thought it only fitting on my behalf to post here considering I do use a highly effecient hybrid horn speaker[Tannoy Westminsters] as well as a couple of other systems with e-stats. Considering you are already familiar with the voice of the 57's, and currently own a pr of 57's as well as the deccas..... if your room is not overly large, perhaps you should consider acquiring another pair and do the HQD system. Still an incredible experience in the right room even without a sub, and the bass panels of the 1D's really blend well with the quads and in my experience,much better than subs with cones. RE: your reservations regarding crossovers...You can experiment here on the cheap, run the stacked quads full range and just cross the bass panels with the cheap little paradigm x-30. Although the X-30 is pretty much usless for the quads,it's a very competent cross for the bass panels.Allowing you the flexibility to adjust for gain,crossover frequency and more importantly for phase.If your intent on crossing the bottom octave from the quad, the older dalquist x-over is passive on the top and active on the bottom, the earlier ARC crossovers were also passive on the top and both can be had for very little money today. The Bryston crossover is also a very good one although perhaps a little more money. I suppose I should qualify myself here... I have been an E-stat fan for most of my adult life, used the stacked 57's with 1D bass panels for years as well as various acoustats,Dayton Wrights,single x-8 MK3's, stacked xg-8's with ribbons] and Soundlab A-1's. I am still using a pr of 3 panel acoustats as well as the Dayton Wright's in another room. To be candid here: After working with various vintage altecs,Jbl's and Klipschorns in pro sound applications, I have to admit to never really being much of a fan of using horns in a typical home enviroment.