Kim, got another?

I have a pair of DX 12's that I am trying to break in for a friend. I am curentlly playing a 10 Hz signal through them. They are wired in seriese and hooked up to 1 channel of my home reciever, which puts out 100watts per channel. It maxes out at 5 on the volume knob and I have it turned up to about 3. It is a Sony reciever and I have a fan blowing on it to keep it cool. How long can I keep the reciever playing like this? Or do I just need to keep an eye on it. Do I have enouf power going to the woofers to break them in? The cones are moving a pritty good amount. They are also out of a box. If my reviever will handle it would it hurt the speakers if I played them like this for the full 40 hours non stop? Thanks allot