Hard to say without having some data to study. Darren's project with 2" drivers responded well to a 31 band EQ for on axis. A 31 band EQ should be cheap but I like digital equalizers with parametric EQ capability the best.

Note that EQ can clean up the on axis response but look at the 30 degrees off axis plot for Darren's project to understand the shortcoming of a full range driver array. No way to recover this off-axis performance.

Jim