subwoofer lowpass filter

Hello, a year ago i got some "decent" set of 2.0 active speakers, it has subwoofer woofer and tweeter, my problem is that the subwoofer play mid or even high freq sounds and when the bass drops it just sounds distorted. I connected a 300uF 200v capacitor and it removes some of the high and middle sounds. The woofer and the tweeter has its own pcb with capacitors on it. When i'm connecting the capacitor, the woofer and the tweeter is affected. I tried to put a diode but then its sounds 100% distorted. Here's how it's wired togheter.

http://imgur.com/a/NPvbL