Blown Subs? Options

[6gsillyca]

how can you tell if you blew your subs? i think i might have blown mine but i am not sure. when the bass should be hitting hard the sound the subs make is kind of a wierd rattling/blowing noise. im not sure how exactly to descsribe the sound. it almost sounds almost like when you have a slurpee and suck out all the juice, and your just left with the icy parts, the slurping sound. i know that a bad description but its all i can think of at the moment. also, when i play with the rca cables (take one out/ put it back and take other out) the rattling sound stops somewhat but subs still do not sound as good as they used to.

could my rca's just be shot?

and im not sure if this matters but it used to go through a 1.0 farad cap until the cap ground came loose. they still worked fine for about a month with the cap disconnected until today when wierd sound started comming.

system is 2 4ohm PG xenon 12", 1200.1 xenon, kenwood ddx7017 double din dvd

thanks for all the help