One speaker louder than the other

I just purchased a new paradigm reference system. It consists of 100v2 for the fronts and 40v2 for the rear. Upon
applying the test tones to adjust the speakers, I noticed that one of the 100 and one of the 40 had a distinct crackle to them the other 100 and 40 did not. Seeing this as a little unusual I hooked the 100 and 40 that had the crackle sound up to the speaker wires from the 100 and 40 that did not make the noise. After going into the test tone once again the speakers had the 100 and 40 that crckled still crackled and the other 100 and 40 did not. I then pulled out my spl meter and the while playing the test tone. The 100 and 40 that crackled played at around 4db lower than the other two that did not. Could this mean that the 100 and 40 that had the crackle-sizzle noise have faulty tweeters or could this be another type of problem. Any help would be very appreciated.