I have a SPL-D 1500D powering a AA Havoc 12 in a box that is 2.2cuft and tuned to 32hz.

It plays the low end immensly (<36hz) but on the 40hz+ it doesn't do so well.

Amp settings are LPF at 63hz, subsonic approx 30hz.

Voltage is good, always at 13v or above.

Any advice ?

How do you know that?

There is a noticeable dip in output.

Obviously these Hz boundaries I have quoted arent precise but rather an estimate.

Should have been clearer in the first post.

On Rap etc it has insane output for a 12, on other punchy/higher bass note songs (I.E Trance/Drum and Bass etc) the output drops.

Tune higher?

Are you are certain that your enclosure is optimal for your subwoofer and listening tastes? Have you checked all of your settings in hu/processor(s)/amp?

Sometimes enclosure placement in your vehicle will cause response peaks and dips. Have you played with enclosure placement?

bass boost is off on amp and hu?

I went by what AA recommend.

There is no bassboost on whatsoever, don't believe in its usefulness.

Could try firing the sub upwards, but as its a hatchback every boot install I have had always had a rear facing enclosure.

Are you absolutely sure it's tuned to 32hz? Although 99% of the time tuning is usually off on the high side, it's not impossible that it could be tuned much lower causing response problems up higher. Although I'm with edub on playing with placement and orientation and triple checking all the settings.

My initial guess would be that it's simply a bloated low end response. Experienced the same thing when I tested the Dcon ported. My solution was to EQ out the bloated low end and increased the level on the sub channel to give a little more punch on the top end while staying within the thermal and mechanical limits of the driver.

The box may be loading on the vehicle and lowering actual in-vehicle tuning -- making the low-end much more powerful than the upper end. Not necessarily meaning no upper-end output, just too much bottom end.

Moving the box around may help -- also try disabling or increasing the LPF in case the knobs are not accurate.

The box may be loading on the vehicle and lowering actual in-vehicle tuning -- making the low-end much more powerful than the upper end. Not necessarily meaning no upper-end output, just too much bottom end.

Moving the box around may help -- also try disabling or increasing the LPF in case the knobs are not accurate.

Just for testing, wouldn't want to leave it off permanently.

Run your test tones where you think it lacks output and start turning the lpf up. If there is an increase in output then perhaps your silk screened label for the lpf is just off and the lpf was set too low.

But you don't want to have the lpf set too high either.

What they said about moving the box around. In my car I can play well below my tuning freq with it facing a certian direction. It can make a huge difference sometimes.

If the sub is brand new, let it some time to ...break in ! In a hatchback, try to have the sub firing up. It may be better !

My btl was surprisingly low when I first played with it. But it became normal a few hours of play later !

I agree with letting the sub break in. But in 90% of the hatchback installs I've done, subs up port back, but give the sub some room to load correctly off the hatch.

reduce the box volume, it will tighten things up on the the upper frequencies.