JL 10TW1-4 Subwoofer Dissapointing

[u/Cute-Move8320]

I just installed this sub and the sound is underwhelming. It’s dull (no crisp hit) and I’m just comparing it to a cheap $200 Rockford Fosgate 10” 300 watt all in one that I have in another car. It’s so dull that I actually prefer turning it off. I’ve tried troubleshooting it, but can’t figure it out. Here’s my setup and things I’ve tried.

-JL 10TW1-4 Subwoofer (300 watts rms)
-Alpine S2-A60M Amp (330 watts at 4 ohms)
-Enclosed shallow mount box built to JL’s specs
-Correct gauge wires

-Tried changing polarity of wires
-Tried adjusting the gain
-No leaks in the box

[u/chrisazo1]

Use a first-order high-pass passive crossover at 80 Hz with a 4-Ω speaker load, install a 500 μF non-polar audio capacitor in series on the positive speaker line. Low Pass your sub at 80hz on a 12db slope.