2cj- As I posted earlier, I have a lovely pair of SC 3's. Early on I had to have the tweeters replaced with a pair that were supposedly matched, but obviously independent of the speakers in my living room (a voice coil was sticky....made a sort of buzzing sound, like a dusty pot. You could fix it by gently pushing in on the dome, and it would go away.) I replaced the tweeters myself and they sounded just fine! (At the time, Dunlavy provided them for free).
Regarding the needs of a sub; my SC 3's are rated only at around 43k at the low end. Occasionally I turn my sub on when I'm in the mood for some meat and slam. But I have to say that 95% of the time, I don't use it. And I can imagine that with the SC4's, you'd be better served without a sub, and could possibly over do it, depending on the type of sub you get. For me, trying to integrate a sub into the mix is tricky, because certain low frequency instruments can have many different footprints depending on the instrument itself, how it's miked and how it's mixed. So, I'm constantly futzing with the adjustable cross-over roll off dial. Without a sub, I let the speaker's crossover do all of the work. Then I have two hands free; one for the volume on my remote, and the other for my martini.
Give it a whirl "au naturel" for a while and see how her bottom feels (sorry, couldn't help myself).
Good luck. Keep us all posted!
