Help with selecting crossover points for a cz702
I recently bought a clarion cz702 due to everyone on here saying how much better an active crossover is! Upon installing everything, I can not get the sound I need. On certain songs I missing much of the frequency. I'm running the cz702 on 3 way mode (that is tweeter, mid, and sub.) When I crossover the tweeters too low they get insanely bright. (To the point of being painful). When the woofer plays too high or too low it distorts. I'm very frustrated at this point. I have spend a good portion of yesterday trying many combinations, but I'm unable to find a suitable solution. Does anyone have good crossover points they can suggest? My woofers are JBL p660c woofer. From JBL's website it has a frequency range 45Hz–23kHz which I'm sure includes the tweeters (I'm only using the woofer, so I'm not sure how high the woofer can play). and my tweeters are MB Quarts OTK-30 they have a frequency range of 3,200-30,000Hz.
Also I'm unfamiliar with crossover slopes, I have tried both 6db and 12db slopes on many combinations and cannot hear an audible difference. I have read much about slopes, but can't understand how they affect sound. But some crossover points would be great! Any help would be greatly appreciated.