Especially if your processor has a limited amount of taps, ie 2048 or less, it is wise to start with parametric EQ in the lowest frequencies, under 100Hz with manual EQ, and then measure again and automatically calculate the FIR correction. To ease this procedure, you can use REW sofware, import into REW the files named xyz-MMM-(LR)rew.wav in DRC folder as audio data, apply a 1/48 octave smoothing, and use the REW EQ function to find the best low frequencies EQ.
Even for higher taps value, this strategy can be a good one : first do manual EQ in bass before to calculate FIR.