Since your clueless, I'll explain. As you know/may not know, gonna go with may not know, almost amps come with bass knob to give the user flexibility to control the bass/amp whatever you wanna call it. In all my years in car audio, I've NEVER seen a control knob mounted IN THE BACK on top of the sub enclosure. What good does that do for the person? Absolutely nothing. They are meant to be mounted close to the driver, popular areas include under dash, nestled in the center console, etc. My big mono amp came with a control knob. I just choose not to install it.