Originally posted by vasyachkin you ASSUMED that a tweeter normally sees a considerable portion of system power - this is not the case. a tweeter crossed at about 4khz normally sees about FIVE PERCENT of full-range power. that is if you put 100 watt clean power into the system the tweeter will get 5 watts average. this tweeter if rated 100watts can in reality only handle 5 watts, cuz that is all it needs to handle. now you clip a 20 watt amp into it hard and it now sees more, lets say 10 watts - it dies.
you are not believing me, and the reason is that a tweeter sounds just as loud as woofer, but this is a psychoacoustic effects. most music energy is in fact in midbass and bass, but it APPEARS that energy is more or less evenly spread out.
just to be politically correct, short-term transients in treble do reach high levels, perhaps 10-20% of total power, but those are too short to overheat the tweeter voice coil usually.