The CR-1 has been a very impactful addition to my system for 2 years now. The main improvement was unexpected; the speaker's (high frequency and midrange) output became clearer. JL explained that it’s due to the speakers being alleviated from the lower frequency bass duty. The cross overs (on the subs) cannot do this. The CR-1 is excellent.
@ozzy - I can’t imagine using 4 of these JL F113 beasts. I have 2, my room is 18X20x9 and the bass is very palatable in the listening locations. The bass must be extremely uniform in your room. Best Regards.