Controlling subwoofer bass separately from other speakers?

I bought my tundra new in 2019.
And bought stereo components from tech12volts
I have two 10 inch jl audio subs in box
With a jl audio rd900/5 amp driving them.
As well as tech12volts replacement speakers in dash and infinity door speakers.
Amp is connected to truck where factory amp was located with tech12volts install kit.
I also have a knob in center console to adjust the amp.
I've been very happy with this system so far
And like the factory head unit and don't plan on changing it
My problem and question is .
That when I turn up amp from the knob it seems to turning up the bass in all the speakers.
And when I go into stereo settings and adjust speakers to the front position all the speakers go silent.
If I adjust it back to the center or to the back the sound returns.
So I'm assuming everything is being ran from the rear position.
And left and right adjustment is reversed. Not a big deal.
My question is what do I need that would enable me to only have the bass knob adjust the subs . And not have that extra bass going to the doors and dash.
And be able to adjust the doors and dash separately.
Hope this makes sense to someone.
As many of these kits that tech12volts sold surely someone else is having this issue.
Thanks for any help provided

 

Check a couple of things... since you say the bass knob adjusts bass in ALL of the speakers and adjusting the head unit to front only turns off all the speakers, make sure the the amplifier is in 6 channel mode, not 2 channel or 4 channel. Also make sure that you have your RCA's plugged in correctly as it sounds like you have swapped something or an incorrect setting on the amplifier.

 

If I manually adjust head unit to the forward setting nothing plays sound.
I'll check all the amp connections you suggested and see if I have something wrong.
Thanks for replying and help

 

Out of curiosity, what wires did you draw the signal from? Rear speakers, one side or both?