im pretty new to the car audio scene, and i go my system set up a few days ago. the sub is an audiopipe tsvr 15, and the amp is an audiopipe apsm-1300. the sub is 500wrms and i have it wired for 2 ohms, and the amp is 600w rms @ 2ohms. Today i turned it up quite loud and it made like a popping sound. I thought this was the sound of it bottoming out, but how is that possible, the HU volume was only on 40/62, and the remote bass nob wasnt even half way up. Since the sensitivity on the amp is .2v-5v, i turned the gain up a little less than half, because my HU rca's are 2.2v. why do you think it would make this sound and also. how do i know when i'm pushing it too hard? it's in a sealed box so i can't smell it. And is it possible for the amp to be putting out more than 500 watts rms at the settings described above? thanks guys.