snare rattle when playing

Why are the snares rattling when doing rolls on the mounted toms?Never had this problem so was wondering if its because of the cheap quality that came with the kit.Snares are as tight as they can possibly get.I already got good quality drum head replacements but still have that persistent rattling....Guess while I am at it,also need to know what Zildgian cymbals are best for rock style playing but aren't heavy sounding.Want quick crashes and quality ride and hi-hat(maybe soft rock sound)