I now am the proud owner of the SDA 1C's!!
This is my first pair of SDA's and I can honestly say the sound is nothing short of amazing. Talk about depth and spaciousness! The difference in the same music I've had for up to 20 some years is really neat. The details are awesome. After listening to these I can't believe anyone, anywhere would want to listen to any other speaker. I don't have the exact set-up Polk recommends for listening and it still does great.
I tried them with and without the interconnect cable. Observances without the cable - dull, lifeless, VERY closed in. With the cable - open, spacious, detailed, room-filling (with little volume which I very much like). That got me thinking. I suppose it's not a right comparison to just switch the cable on/off since the stereo/dimensional drivers are wired differently within the crossover. It might be neat to have a pair where all the drivers are wired for stereo like a regular speaker, then do the comparison with the cable on a correct set. If I remember correctly the dimensional drivers aren't in stereo when the cable is not plugged in, hence, I would think, the extremely dull sound. Even my 8t's sound better without that cable plugged in.
I almost forgot what the SL2000's sounded like. Definitely brighter than the RDO replacements but they still do shine with the brass instruments as long as the volume is not high. Will I do the upgrade for the tweets? Maybe but not right now. My wife was ok with them BEFORE I had them set-up in the living room. After she saw them she said she didn't like them there. Told her that SOMEDAY I WILL HAVE MY VERY OWN SOUND ROOM!!! Until then she just had to put up with them. She couldn't deny the sound they put out, however.
The gentleman I purchased them from was the original owner and stated they stayed in the same room in the house since he bought them, in 1988. He gave me all the literature he had which included two advertisements for Polk in booklets which talk about all their different speakers, at the time. Wow, $800 per speaker back in 1988 was alot of dough. No wonder it took me 20 years to get SDA's!