The HSU will dig deeper and is built better too. The EMP would have more output in the 35-80hrz but thats about it. The HSU/Outlaw has a better driver too. The HSU and other ID brands have been tested and perform very well, the EMPs subs have never really been highly reguarded. Every comment I could find on various other sites have questioned the EMPs built quality, low powered amps and performance. HSU, Emotiva, and Outlaw are probably the highest reguarded subs in this price range.