ARGHHH I just had a long post and hit back by accident!!!!!!
Ill say it again now but it won't be as good. Clipping your speakers actually refers to driving them with a clipped audio source. As Andrew said clipping turns the smooth audio AC waves to flat DC. This DC does nothing more than HEAT up the coils in your speakers, causing them to burn out. At the same time this heavy current load will heat up the Amp and is the no1 cause of amp failure.
NeX if your having to replaces fuses that often sooner or later youll fry your speakers/amps or both.....
Truly overloading a speaker is actually quite hard, and almost ALWAYS the cause for blown speakers is again an amp that was 1, not power full enough and two been driven to clipping. However in rare cases, with very very excess amp power it is possible to kill a speaker with a pure signal.