Another fun tool is a simple App on your phone. Spectroid is a frequency measurement tool. Take your phone and sit in your listening position. You will see the bass response in relation to other frequencies. make sure the recording is one that has low frequencies. Most don't have much below 35 Hz but some recordings go to 25Hz. Make sure the bass is as loud as other frequencies, kinda close, not louder. During my placement wars, there were times the bass completely cancelled out in my listening position! Now I have beautiful, detailed bass.
I have traps. Quite a few, but not enough bass traps. There are rectangular and cylindrical(best}f, corner triangle, also good. you can also add traps with paintings or pictures, at a cost.