Yamaha DTXpress/DTXplorer/DTXtreme

I did a search and did not find a similar query. I have just 
connected my system and it seems that the bass drum is not picking up 
every time i hit it. I am wondering if the pad has a break in period. 
Is the pad just not sensitive enough and needs a good stomp on the 
pedal? Perhaps the volume on the brain is not loud enough and i've 
tried tinkering w/ it to no avail. I have them connected to 
headphones and everything else is working great. 

This is my first drum set so i'm not sure if there's a proper load of 
force i need to put on the pedal in order for the pad to pick up the 
noise. Obviously w/ an acoustic set i wouldn't have this problem, So 
does the pad just need to be broken in?