this unit look great , sound great , and the price be unbeatable . the overheating seem to be cause a lot of people problem , if not for that I would give this unit 5 star . if you have some gut and some basic knowledge about electricity and electronics you can avoid these problem . I get a really good deal on one , then find out about the overheating . not want this to be a problem I decide to investigate . I pop off the back panel of the sub to find that the fan be not actually work . I imagine that it be suppose to kick on when thing start get hot , but my unit be already really hot . the heatsink inside be almost too hot to touch . the fan be 80mm so I take a standard lead case fan and replace the stock one . the stock one have some non standard screw hole so I have to use some strong adhesive foam tape to hold the new fan in place . then I run the wire outside the sub and rig up a small ac\/dc power adapter to power the fan . it take about 30 minute to do and now my unit run very cool , and have a cool look blue glow on the wall come from the fan to boot . you could just use the stock fan and rig up a adapter to it but I do not want to cut off the connector in case I need to take the unit back . for the adapter use something between 7 and 12 volt , lower voltage = quiter fan but less airflow . if you do not want to open it up , you could just mount a fan right on the outside of the vent . I think the major problem be there be a defect in the board that do not turn the fan on , and you do not want a bunch of really hot electronics with no airflow .