Quote Originally Posted by amant02 View Post
U sir are correct. That's cadence top amp. It comes wit a bass control unit.

Idunno why its needed wen a descent headunit will probs do it better.
the sub control on these amps is more like a volume switch, its a handy function to have head units tend to control the amount of bass signal sent to the amp, these controls increase the volume of bass which is put out if the amp is used in a low frequency.