too vague. there are some full range speakers out there. also depends on speaker. some speakers just have a natural roll off at certain frequency ranges so it won't get damaged if you play with no low pass. what speaker are you talking about?
im experimenting with rear fill - i wanna try without tweeters.. but my crossover has a roll off (and i dont know what the speakers natural response is) so i wanna test it if i hook it up without the crossover just to the midrange speaker... but i dont wanna blow anything up