jl 12w6's 500/1 amp

the slots are 16" deep, the box also has a divider between the two speakers. I don't know if that changes anything. It is made from 3/4 mdf board.

this is what the box looks like

Allrighty pman, here's your box: ~ = about Gross External: 5.5cft. Port Displacement: ~.75 cft. Wood Displacement: ~1.35 cft. Woofer Displacement: ~.18 Total Net Internet Volume: ~3.22 For our purposes we'll call your box 3.25 cft eh? To be honest, that thing works out to be *extremely* peaky. Here's a text of the graph: Driver            : JL Audio 12w6v2 Project by        : sedate Project for       : pman187 -- Number of drivers : 2 Box type          : Vented Box size          : 3.250 ft^3 Tuning frequency : 48.00 Hz Vent              : 2 vent(s)                     15.86 in length for each                     2.50 x 12.00 in rectangle                                                                                                                                        Relative                                        Freq        Gain        SPL                                [Hz]        [dB]        [dB]                             20.00        -22.58       66.34                             25.00        -16.14       72.77                             30.00        -10.93       77.98                             35.00        -6.38        82.53                             40.00        -2.20        86.71                             45.00        1.71        90.62                             50.00        5.03        93.94                             55.00        6.93        95.84                             60.00        7.10        96.01                             65.00        6.37        95.28                             70.00        5.49        94.40                             75.00        4.70        93.61                             80.00        4.05        92.96              Around 60 hz or so you have a biggg peak... then a total fall off down to 30 hz or so. Here's how I would set your amp, just shooting from the hip: Gain: NO MORE than 1/2 way up. I had a pair of 12's off that same amp (MUCH smaller box) on a 4v preamp and it started clipping really hard about 2/3's the way up. Center Freq: I'd put this about 40 hz give or take a little ... help bring up that fall-off under 50 hz that box makes. Q: Whenever I played with this setting I could never notice a difference.. still, I'd leave it about 1.1 - 1.5... this you can play with a bit to see whatcha like. Subsonic filter: Your tuning frequency is *really* high. Set this to 35hz to protect your subs from bottoming out... your reponse sucks that low anyway. Lemmie know how this sounds huh?"I'm finished!" - Daniel Plainview

what do I want to set my amp lp filter to? the filter freq? Or is that the subsonic filter? there are 2 filters the infransonic filter& the filter freq, I am kinda confused. Also where would you recommend to set my deck?

Leave the xovers on your deck alone. Cascading xovers is redundant and gives you unpredictable results. Set your LP to 80hz. I don't care what your mains are set to, leave your LP @ 80hz. I'd use the 24db/octave setting. Your Infrasonic = subsonic. This is basically a high pass filter with a *very* low setting. By limiting the really low frequencies that hit the woofer, you help protect it from dangerous over-excursion; particularly given your box size and tuning frequency. Try 35hz to start... if low notes don't give you any kinda clipping/distortion, go ahead a lower it bit by bit.. but NO LOWER than 30hz.. never any lower... no matter what. Now, these two settings give you a "band pass" xover... your subs will see 35 - 80hz, with a mild roll off on the bottom (I think the subsonic is a 12dB/octave slope) and a steep roll off on top (24dB/octave slope). The Input Voltage setting should be set to "high" .... between you and me.. you have a really nice deck. What kinda highs you running? What kinda amp? "I'm finished!" - Daniel Plainview

so I want to set my input voltage should be set to high. I have it on low right now. Every time I set it to high it seems to get quiter. I'll try high again. My highs are 6.5" infinity in front and infinity 6x9's in the rear. They are the lower end model which ever those ons are. They are running off a old rockford fosgate 150a. Hey it does the job and is not over powering. So if I set the input voltage to high what will that do? I really appreciate all the help. I did set the settings to what you told me to without the input voltage on high and it sounds alot better. I will try the high. Set your LP to 80hz. I don't care what your mains are set to, leave your LP @ 80hz. Is this on the deck or the amp?

Actually, where you set your LP filter really doesn't matter, but *I* would set it on the amplifier. That will give you the most predictable results... as the rest of this stuff is set on the amp eh? Your input voltage is set to "high" because that HU has 5v preouts... (which, as pre-outs go, is ridiculously powerful) it gets quieter b/c the amp is expecting a more powerful input signal. Use the gain setting to adjust for proper sound... perhaps at the 'high' setting you can nudge your gain up bit by bit past the half-way point, but be really careful. If you hear the slightest bit of distortion turn the gain back. You actually would be better off using the "boost" knob anyway... that's really more akin to a volume control than the gain. Try leaving your input on "high" and the gain right about half-way up. Then using the "boost" knob, go ahead and dial up +3dB... then +6dB..   see if that doesn't sound the loudest and cleanest eh? Post back with your results. I'm glad it sounds better. If ya don't mind me asking, how so?"I'm finished!" - Daniel Plainview

I felt that same insensitivity, Paradigm, and I posted a link to the manual in the beginning of this thread.  If that were MY amp I would take that manual to bed with me for some pleasant reading!Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.