my cars front speakers keep cutting out it seems like it keeps happining wheever i hit a bump ive got 2 mtx thunder 12 inch subs wired to the amp they came with i think its only like a 200 watt amp and then my 4 speakers are wired to a seperat amp with is 450 watts i didnt do this the guy i bought the car from did but could somthing be loose somwear because its only when i hit i bump the front ones stop working untill i hit anothere decent sized bump?