There is really not much I can say that hasn't already been said about the SDA's somewhere in the archives of CP. I used to sell SDA's back in the late 80's and early 90's and really hadn't heard a pair in quite awhile. I've spent a small time with the SDA 1C's that I bought from Normanality at the Chicago PF. They were modded by Anonymouse a few years back. Mods include RD0's, Solens on the mids, Sonic Caps Gen I bypassed by Sonic Cap Gen II on the tweeters, Mills resistors in the x-over, Vampire binding posts and a very user friendly bananna plug connection for the I/C.
They are simply an amazing sounding speaker, definetly a bit uncoventional in the way they present the sound stage (not a bad thing), but simply amazing the amount of detail one can hear in all recordings. I am hearing things that used to be buried in the mix that I never knew were there, very subtle little things. The bass is amazingly clear, deep and tight and very very clean. Low level resolution is excellent and there is cohesiveness to the presentation that is downright euphoric. Recordings with extreme R/L info can be a bit over the top, but I'm sure I'll get used to those extreme mixes.
I don't yet have a compendium and I can't seem to find a user manual anywhere online. PolkSda.com has been a good resource but I need to get some pointers for getting these tweaked perfectly. Right now they are approx. 6 ft apart measuring from the tweeter centers, and approx. 11 inches from the back wall. My couch is flush against the opposite wall about 6 ft. away. I'm sure having the wall right behind me while listening isn't ideal as I get reflections immediately and I notice even sitting forward on the edge of the couch changes the sound a bit.
The thing I've noticed in the short time I've listened is a lack of front to back depth of the center (non SDA) soundstage information. I have a rock solid center image which is just at the front edge of the speaker plane. Different instruments float around R/L between the speakers and of course I get the SDA effect outside of the cabinets, etc., just no depth. I was very used to getting a farily deep soundstage with my RTA 11T's and the LSi 9's. I hear of people getting decent fore and aft soundstaging but so far in my short time I haven't been experiencing that. Other than that they are really beginning to become addictive.
I hooked my 9's back up for comparison, which isn't really fair, they are two completely different animals and the 9's sounded so flat and 2 dimensional and closed in and compact. I really enjoyed the 9's and for a small bookshelf they are an amazing speaker but the SDA's are more to my likeing. There just is no replacement for displacement. I will say if anyone can come up with a way to incorporate the Vifa tweeter into the SDA's I'm there. I still prefer the Vifa even over the RD0's. SDA's with a Vifa tweeter(s) would certainly take it to the next level.
I'm open to any and all suggestions, links, ideas, etc.