No Dave, I have not heard the 1801, although I am quite facinated by the info on your web site about them. They are quite impressive by numbers and even more visually impressive. I would love to hear a pair of your speaks, but alas don't know how that would be possible without spending the money. Even building them on my own would cost me large, considering the cost of the drivers. I really am interested in a low bottom end, although 40hz isn't that bad. My current Sililoquy's claim to go down to 35 hz@ -3db. A freind is in the process of creating a tube amp somewhere in the 90-100 watt output and will need a pair of quality speaks to complete the situation. I'm pleasad to say that after 4-5 years of helping me with my audio, he has finally caught the bug. My wife just looked at us as we were taking apart my pre amp this aft and shook her head. It's all about the enjoyment! I'll do a seach for the Diapallito design. Thanks Dave.