At low volume it sounds as if the subs turned off. Sq is fine but a horrible turn off pop on the subs. Gains have to be turned way past where any amp I had were. You also have to have the bass boost turned up just to get any low end out of the subs at low volume.
Controls on the ends are fine and work as intended.
Comes with the bass knob for the front . Maybe I got a bad one.. Expected more than what I have out of this company. Feels nice and heavy solid construction .