Your EQ should not be at powerful Keep it at flat and rest your gains again its completely set wrong and the EQ will screw up your bass and kill your subs All bass frequencies should be flat. Anything above 80hz can be tampered with to get the sound you want but underneath that is forbidden. SLA should be at 0. Low pass filter on the amp should be wide as in the higest it can go. You want to use the low pass filter on the head unit set to 80hz. Low pass cuts off the frequencies above so it blocks out vocals from the subs. However, if you set it too low like you have with your amp ATM, you are missing out on all the kick drums aka midbass from rock and metal.
Gains should be reset set again properly after these changes. Volume knob on the head unit should be as high as your speakers can get without distorting. Then play a bassy song and slowly turn up your gain. When you hear the sub start changing to a different pitch, then you need to back up the gain a bit. OR if it stops getting louder, that means you are at clipping(dangerous levels) back it down slightly if that happens.