There is some physics around the wavelength - remember that microwave energy is very harmful to health and 800W of it in your kitchen is quite capable of heating your eyeball content making you blind, maybe even dead. However - it doesn't and weirder on the surface, is you can see into your oven when cooking. 800W of microwave energy inside and a bit of perforated metal in the door letting the light out, but not the microwaves. It's because the holes you can clearly see are still a barrier to the microwaves which are longer wavelength than light. Your hole is the same as the microwave - but scaled up. The wavelength of the bass cannot escape through a small hole, like the microwave energy, but of course higher frequencies can escape. Clearly sound travels differently, speed wise than microwave energy, but your kick might have a wavelength 8m long which would have to be aligned quite well to let the sound out.