I just bought a used DTX502 kit. I am noticing that when I try to hit the hi-hat with it open, quickly, during play, it is quite unreliable. Sometimes I get an open hi-hat sound and sometimes I don't. If I do it slow it works, but not if I'm trying to do it fast. Is this a limitation of electronic drums? Is there a setting I can change? Is there a way I can set up the hi-hat (height, etc.) to improve the situation? Or do I just need to hit it differently? Thanks!