i would say that there hearing is nominal. my roommate has 500watt paradigm system. it shakes things off the wall, Morken doesn't seem to be bothered by the overall sound or even massive vibration. unless he is sleeping that seems to make him react. even then he just moves to a part of enclosure that is not near wall. then he goes back to sleep mode. on the other hand we have a door that squeeks real bad that he seems to hear whenever it opens. so i would have to say they can hear some frequencys.