MMC6500 tweeter cracking!

clanton1.8T

hello, i'm having a slight issue with my component tweeters. i have had them hooked up for about two months now and they have been great. until the last week or so. i have the components hooked up with the C400.4 amp. recently at higher volumes(20-22) i can hear cracking and popping from the tweeters. but they are clear sounding at lower volumes(15-17). only recently have they done this i was able to listen to the stereo at th higher volumes and it all sounded great. well i guess thats enough for now, any help would be greatly appreciated.