I have a really nice xtant 2200i amp, if you know quality you know xtant, this was rated at 200watts, which is beyond an underrating. The sound quality out of this is suberb I was running my focal Utopia's off of this. I have also run an infinity kappa perfect 10, and it hit really hard. I am clearing out some of my car audio stuff. I have switched out this amp because I found a soundstream human reign and that amp is something I have craved for along time. This amp when it was new was over 700!!!! I will let it go for 150 shipped plus paypal fee. The crossover frequency is for mids and highs. you can get the chips for subs on ebay for very cheap.