Zain, amps aren't supposed to be loud, speakers are loud. Adjust your input sensitivity if you're not getting the power you want, check your input (power) voltage, or get a better sub.
5 Stars on this one, everything you'd expect from JL Audio in a very small package. I'm driving a 12W6v3D4 in a 1.0cu/ft enclosure (wired at 2 ohms) with this amp and it drives hard and doesn't overheat! JL voltage settings are conservative to allow for cranking the head unit sub level/bass boost after input is set. Plenty of headroom with this amp, no distortion or clipping even when driving well above rated voltage output.