I think everyones advise is pretty good, having done quite a few stereos in my day with varying complexity it is hard to get a good sound just by looking at your system. Much of it is personal preference as well as the type and power going to each tweeter/midrange/woofer/subwoofer in your system. All that being said, I have a few suggestions.
First off, keep the low pass filter as low as you can get away with. larger cones were not made to handle anything, honestly higher above like 60-80 Hertz.
That being said, I don't know what the RCA voltage is on the head so Here is a rule of thumb I follow in initial tuning of my amplifiers.PUT YOUR EQUALIZER ON FLAT. On just a subwoofer setup,turn the gain all the way down and turn an average song up to as loud as it will comfortably go (no distortion in your mids/tweets at all) or as loud as you would care to ever listen to it. Then simply adjust the gain on your subwoofer amplifier till the clip light just lights or if there is no light, you hear audible distortion. At that point turn it down just a hair. This is a good way to set up an amp in a way where you have minimized your chances of ruining your subwoofer or amplifier.
Third, ONLY USE THE LOUD AT LOW VOLUMES. It is only met to provide an added high and low at low volumes and is never to be used at higher volumes.
Lastly, If you do what ive told you to do and your still not getting the bass that your looking for, you may manually tune your EQ on your HU to provide a bit more bass. Don't go overboard, use the LOUD at low volumes, and manually crank up the EQ a bit at mid volumes but if your nearing the upper range of your systems volume use a FLAT EQ setup.
No need to be embarrassed about your setup! Rock it hard! Tune it right! Make it beautiful and show it off. You still have a better system than 95% of us! Hope I helped.
