The article is talking between 8 and 37hz, iirc. General given hearing range is 20hz to 20khz. So the vlf is flirting with that range. Throwing in an aside here

The article is talking between 8 and 37hz, iirc. General given hearing range is 20hz to 20khz. So the vlf is flirting with that range. Throwing in an aside here, inaudible might be a better word than undetectable. I was always told just because you can’t hear it doesn’t mean you can’t feel it, for both high and low end. As for why you might want to dampen inaudible low end aside from a fastidious want for control, or not wanting a build up of that feeling only for some lucky punters, you might just not want to shake a ceiling tile loose or a vibrating air duct might be annoying: there is more energy in the low end.