Summary: The bass impact is insane. Its so bloated and over-exaggerated that even female voices sound bassy. Its like listening to a poorly configured 16" subwoofer. So yes, it is shocking such bass is possible from canalphones, but after a while, its just too much. You cant listen to a talk show without hearing deep bass in the voice of everyone. Coupled with non existent mids and shrilling highs, they make up for some really poor listening experience in the long run.
Summary: The Sony MDR-EX71 is seriously overrated by quite a few people. The bass is boomy and uncontrolled, and the highs are painfully screechy. The mids are also undistinguished, as well. And though the MDR-EX71 is comfortable to wear, it is extremely difficult to get a proper seal with the supplied sleeves, resulting in mediocre isolation. You get what you pay for, in the case of in-ear 'phones.