resonance and sealed enclosures

I was wondering: suppose you have a smallish sealed subwoofer with a resonance frequency of 40 Hz (obviously not up the quality of the things usually talked about here). This is right at the frequency of the low E on a bass. My concern is that the reponse at 40 Hz will be exagerrated. The resonance peak on a sealed sub isn't important when it's 20 Hz or below. Will the 40 Hz resonance really matter?

I am thinking about using this sub for computer speaker BTW.