Need advice on head unit settings

[chewychewbacca]

Hi guys, I upgraded to a Pioneer DEH-6300UB deck and added a powered sub, placed in the back. I am new to car audio and would like some advice on if I am doing this right for the optimal sound. I am still using the factory speakers. With this upgrade, I wanted to take the strain off the speakers using a subwoofer.

With that in mind, my head unit right now is cutting off anything below 125Hz and sending it to the subwoofer. I can change it to 50, 63, 80, 100 or 125 Hz. Is 125Hz and below a good range to send to the sub or is there a better zone?

The High Pass Filter setting is set to 125 Hz as well, to send anything above that to my factory speakers and cut off anything below.

Is this a good way of getting better sound quality? Should I set this lower to complement the bass or will I get better sound only sending greater than 125Hz to the speakers?

The last thing is on my powered subwoofer itself, should I set the Crossover Frequency to the highest (200Hz) so I control through the deck? This is weird because the deck goes only up to 125Hz. I am not sure at all what to set this to so I set it to the highest.

And the other knob I am not sure about on the powered sub is the Level. Currently I have my Head Unit Subwoofer level setting at 0, and I'm adjusting the level through the sub. Is there a better way to do this? Should I set it really high and then bring down the level on the HU?

Any advice you guys could give me would be very appreciated. I know that all this stuff can be subjective but I am very new to car audio and don't have a solid starting point for me to tune the system. I think EQing will have to come when I have more experience and more of a ear for this, I just have it on a preset / flat currently.