There is nothing to grasp the primary excitation of resonances is through the air not the cabinet. You should take a couple of minutes and look at a couple of speaker reviews and see just how much energy is being radiated by the cabinets by looking at the accelerometer plots from the cabinets. If there is anything it is typically high Q and no where near the energy from the drivers.Compared to concrete it might as well be cardboard. However it doesn't matter, yours is still an apples to oranges comparison. Strange your not grasping it.