If you haven't done so already, replace your engine mounts. Also, bad axles can cause a vehicle to vibrate, not just unbalanced wheels.
if the vibration is above the range of human hearing which is about 20khz
mainly two types of Vibration measurement: shaft vibration Bearing Vibration
Epicenter
it is right above the drain plug onnthe bottom of the tranny
behind the motor.. between the motor and firewall, just above the cv shafts
There is pressure in all water because of the weight of the water above it pressing down
autesian
Driving at 50mph or above what causes a loud knocking clicking sound during acceleration?
It is probably an out of balance tire, next check wheel bearings.
check the front shocks or struts to see if they are worn out, worn out struts could cause the front tires to hop at higher speed.
It is the weight of the water pressing down from above. The greater the depth the greater the pressure.
Because as you climb higher there is less air above you pressing down on you with its weight.