If you had only one listening position, I suppose sufficiently accurate EQ might be a solution. But what about ears that will be listening three, four or six feet from yours? How do you EQ for them separately? Many people, for about the same cost (or less) than accurate, narrow band, low-frequency, automated EQ, add a second subwoofer placed such that the "dead zones" of one are filled in by the "live zones" of the other. It is an imperfect science either way, but the second sub option generally works better for rooms which will be inhabited by multiple listeners.