speaker farts

my 3-way 6X9 is farting at certain frequencies; im really afraid that it's blown... Is there any other possible cause of such a noise? It's not constant; it only happens sometimes, but most often at midrange frequencies; There are two tweeters in the center of the 6X9 driver and im afraid one is blown... It's a memphis pr93s, and I dont know how it could possibly have blown... It says it needs 60 W continuous and 120W peak; I have it hooked up to an alpine head unit, no amp; so its only getting like 20 W, so how could it have blown?

I've had the speaker for about 5 months; and only today has the noise started --- it really pisses me off... I wasnt really even listening too loud. The only thing thats changed recently is that I hooked up a new sub to an old crap amp; but thats not even related to the 6x9... I also just put in new door speakers that need the same power; the older ones only needed half of that, but I dont see how this could affect the 6X9.

I dont think theres anything anyone can tell me other than its blown, but im praying for some other answer because i just blew a ton of money on new door speakers, 3 new amps, and a new sub -- I planned to keep these 6X9's because they are so good.