Quoted from flashburn:It's not a sub, it's a woofer. You are expecting too much from a single driver that's being used for a very large range of frequencies. Sure, you could add a bigger amp, but it's still not going to sound great. I'd buy one of those external subwoofer's to go along with it, it really opens up the sound all around because it reduces the workload from the cabinet woofer.
It's the best investment I've made for a few of my machines. You get plenty of thump out of them.
Chris