You really cant guage how fast a sub is moving in and out wiht out a few little toys and some creativity
But what i can tell you is at say 10 hz, you sub moves out 10 times a second (i belive or its doubled, i forget or even halfed)
at 30... 30 times a second
Thats why at really low bass you can easly see the cone moving in and out
Meters have cut off eq points, so your highs and such dont matter.
Below a certain point , bass becomes...for lack of a better way to put it...like an earthquake.
The waves move through your car in a totaly different fasion. The air your subs are moving really dont make the shaky, its the contact points to the frame...
thats why say in a house speaker, stand mounted speakers dont create much of any bass, though they may sound deep, with such a small surface area making contact to the floor very little can be conducted.
You also gotta think, your car is totaly sealed, for the most part, and none of the air (not the soudn waves) that the subs are moving are really excaping the car. Yet the windows on the police station i just passed were definatly shaking. The waves are moving through different conducted through different points...
If i wasnt so intoxicated at the very moment, i could probably spit this out a lot better.
god i cant f'in t hink right now
anyways, its not the air thats shakes the car its the sound waves. and because they move through metal and other hard surfaces much easier, you can feel it that way better. the waves that your subs create dont travel through air as well as through metal. Its really just the surface area of your sub moving in and out, that moves your hair, and gives you that tingly feeling. But its the sound waves that kick your ass around
whatever, im giving up drinking, it makes me too stupid