This is what I got:

Stock (I believe) shaker 500 system . . . woofers in the doors with crappy speakers in the doors and rear deck.

From the rear speakers I have a ->PAC SNI35 Adjustable 2-Channel Line Out Converter ->JL Audio XD600/1: Monoblock Class D Subwoofer Amplifier, 600 W ->JL Audio CP210-W0v3: Dual 10W0v3 BassWedge, Ported, 2 Ω.

My description of current performance is that with the stereo faded to just the woofers is that they drive enough to offer bass but not to what I believe they should.

When I blend them with what seems to be appropriate for a balance between all audible sources is that they are non-existent. I really have to turn up the volume to them to offer a sub-par performance.

Everything is seemingly correct as for installation and turned-up.

What do you think?

 

I'm not sure honestly, but the guys over on the a/v forum could probably get you straightened out.

 

try turning your LOC up and if that doesnt work like you want try hooking the loc up to the sub output of the shaker amp.

 

DUAL subs arent the best quality so they might be part of the problem.

 

Well - unless dual subs have become far worse over the last 15 years - I do not think they are part of the problem here.

 

Make sure you have the fade level ( in the car radio) set to the middle, this sets the rear speaker volume to be the same as the front. If this does not work, you can test the amp and speakers by running an IPOD into the amp RCA inputs. You'll need a cable that matches up, the sound quality will be weird but you should have decent bass volume. If this works, you have a problem with the line adapter. If this does not work, check the amp filters-set everything to the middle to start. If yours has a remote bass level, make sure it is turned up.

 

I'm good now.

I had a bad connection through the line converter.

Thanks