How long does it take to fall 500 feet?

If we look at this in a purely Newtonian way:

Assuming you have no vertical speed at the start, and using gravitonic acceleration of 9.8 m/s2 (exact value varies depending on your location on the planet), such a fall would take approx. 8.6 seconds. By that time you'll be going over 152 mph. Realistically, you would slow down due to atmospheric friction. Skydivers tend to reach a certain maximum speed (before the chute is opened), which btw lies above and beyond what you could reach in 1200 feet.

There are actually record attempts for reaching the maximum possible speed (where the skydiver plummets head first as an arrow to minimise the resistance on the body).

I don't know the full effects of such friction, but can guess that over a height of 1200 feet this won't prolong your fall to beyond 9 seconds.