Set of dome tweeters (Too high wattage)

I have a set of dome tweeters that ran grwat on an old amp i had, thing blew out a few years ago, and just barely runs through another amp with the crossover and woofer. there is some jumpers in the crossover that say Tweeter attenuation -4dB stock setting --- -2dB 0dB Just as i put it right there. I want to know what attenuation means and how i can use the same amount of power into the tweeter, but make it louder. (It's pretty quiet.) Right now it is set at -2dB. Except the dB and numbers are lined up.