Put your subs at mid points on opposite walls ( https://pdfs.semanticscholar.org/00da/51387c572cfd27c0256cb15e44e976a1a72e.pdf ). That will give you the evenness bass response throughout before equalization or the addition of bass traps. In fact, you may find the traps unnecessary.
You speak of having subs, multiple. Have you tried putting them at mid points on opposite walls? It works wonderfully well at controlling the worst eigentones without equalization--- a good starting point before it. The research...