Car Stereos: best settings for my stereo, loudness controls, rear speakers

Question
hello brian,

i have a jensen phase liner UV10 touchscreen with an ample audio exonic exa 2000dx amp connected to 2 kicker 12in cvx's in a sealed box. my question is, what are the best settings i can use for this set up? i know i need to turn down the bass for my other speakers and just use my sub for all my lows but when i tried to do that on the head unit it also turned down my subs. how should i do it with this head unit? also my amp has 3 knobs labeled subsonic, bass boost, and low-pass (LPF). what should i have these knobs on for the loudest bass while still being clear and tight? the subsonic knob is labeled 10-60Hz, bass boost 0db-18db, low-pass (lpf) 30Hz-250Hz. any help would be greatly appreciated. thanks!

Answer
Hi Kyle,

Some head units have a built-in high-pass filter setting that lets you cut the bass out of the front and rear speakers without affecting the sub amp.  However, I doubt your Jensen deck is equipped with this feature; and adjusting the head unit's bass or loudness controls will always affect the subwoofer as well.  Your best bet is just to set the head unit's bass control at a flat setting, turn the loudness off, and use the amp's bass boost dial to compensate.

A subsonic filter is used to remove very low bass tones from the subwoofer.  It's necessary when you're using a ported box, because low-frequency tones below the port's tuned frequency can damage the sub.  In a sealed box, though, the subsonic filter isn't required, so I'd turn it to the lowest setting or off entirely.

The low pass filter prevents the sub from playing higher frequencies that are better left to the front and rear speakers.  This setting usually depends on the size of the front and rear speakers; you'd want the subwoofer to start picking up where the other speakers leave off.  Usually it will fall around the 80-100 Hz range.  

The bass boost dial usually adds more output in the 40-60Hz range. You can use this to give the subs a bit more low-end punch without affecting the other speakers; but remember that you're also increasing the power output to the subs when you turn up the bass boost, so you may need to adjust the gain control down a bit to compensate.

Hope this helps, and I apologize for the long delay in answering your question.

Brian