I've done some horrible crimes against cars, and i'm just gonna guess a scenario here because this is how I did it... One of the front wheels is out of balance, or a shaft is vibrating... This can do what you're saying... But it can also shake a shock loose without you feeling it... Then the little wheel shake transfers through the loose suspension piece and turns into a scarry thump...

When it happened to me the wheel was out of balance, but not the source of the noise... Check your shafts and balance, and go ahead and check for any missing bolts just in case... A shock shaking a third millimeter into a sheet of metal under the hood sounds like the end of the world...

The only other thing I can think of that you might not is a caliper bolt walked out and the brake is slapping... Would explain a brake vibration, and i've done it Out of balance wheel shook the spindle, but not me... I didn't notice till the caliper threw the bolt... One problem caused by another... Ofcourse this assumes you don't just have a belt seperating in a bad tire... Maybe this helps... Stay safe!