subs hit hard sound great one of them pops

[kaden]

hello everyone, i searched the forum for my question and found a few like it but no resolution. i just installed a nice little setup in my truck everything sounds great except one of the subs makes a popping noise once i get to a specific volume, the other sub does just fine. i checked connections and everything and they are good so i am stumped as to what the issue is. here is my setup

HU = Pioneer AVH-P4400BH 2-DIN Multimedia
Amp = PIONEER GM-D8500M 1200-WATT
Subs(x2) = Alpine SWR-12D2 12

i am at wits end on coming to a conclusion with this.


Thank you.