subwoofer barely emits any bass

I have a 4ohm dvc kicker 10" solo baric sub ran in parallel to a mtx tc4001 monoblock amp which is 2ohm stable... had the amp bench tested so i know it works, powers on properly turns on and off with head unit so good remote lead, good ground... i have rca's running from the subwoofer outs on my alpine cda 9853 head unit to the rca's on the amp... i have the subwoofer output on in the head units settings, but even with the amps gain most the way up and the head units sub output up i get just a tiny bit of output to the sub... loosing my mind any help would be great thx...

Play it with only one voice coil connected.  Does it play now?  play it with only the other coil conected, does it play now?Let's Go Brandon Brown. Congratulations on your first Xfinity Series Win. LGBFJB

also your rca from your head unit could possibly be bad.

I hooked each voice coil up to the amp in a 4ohm wired method as if it was a svc sub to a mono amp... each voice coil played but it was the same... barely any bass with the gain way up on both voice coils...

originally i was getting no output so i bought brand new rca's now i get week output...

not your rca cables that runs from the head unit to the amp the actual output rca cables from the head unit itself. Do you have another head unit to test or a friend to test the amp for you??

i had the amp bench tested at a shop it works... i've determined the problem to be the settings of the head unit they're extremely complicated... i used high level inputs to see if it was the rca jacks of the head unit still not very powerful... but while i had the rear speakers unhooked i turned the fader all the way rear and turned the head units volume up and was able to get good power... my problem is that the factory speakers only allow me to turn the decks volume up to 12-15, but the sub doesn't start showing it's power till around 25-28, max volume is 35... what settings on the head unit do i need to adjust to equal out the volume levels of the factory speakers and the sub???

See page 29 of your owner's manual.  The best setting for the sub output is "ON-MONO-SYSTEM 1."  You can also try SYSTEM 2 if you do not want the subwoofer level to change with the volume control.  And the fader has nothing to do with the subwoofer output - I suspect you have the sub connected to the rear line level outs not the subwoofer output if the fade control is affecting your sub signal.Support the12volt.com

The fade control only affected the sub when i had the high level output hooked up... unfortunately the manual was misprinted the cda9853 doesn't have the mono/stereo selection it's printed in the manual corrections section... i do have it set to system 1 also... i'm assuming i need to change the x-over settings and eq settings?