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I really think that you might what to look at a slightly larger enclosure, around 1.75 to 2.25 cubic ft. As the box gets larger the frequency at which it peaks will go lower. The amount of peak should also decrease.

Also with a 3-inch port, make sure you are paying attention to vent velocity. The lower the vent velocity the better. One other thing, at tuning frequency the port makes nearly all the sound so if you can get to 4-inch do it.

A peak at 5db might not be bad if you turn off the Loundness function on your HU off and turn your bass to "flat or 0". You can make the gain work for you.

well 30 hz gives a 2dB gain, in a 1.5' box i would need a 12.6" x 3" port wich would fit, but you're right @ 28 hz it would have to be close to 15" long, might work but would be close to the enclosure walls and driver. wish i had better box designer!! but 35 hz tuning would give a 5 dB gain, way to much to sound good, especially with all the hard rock i listen too

Tuning to 28 Hz in a 1.4 cubic foot box will make for one really long port. I dont think it will fit in the box.


(this was generated for another forum, but I can use it here)

If you look at the ported enclosure tuned at 40 hz you will see that the graph is smooth with no sharp peaks. This box actually sounds awesome (its in my wifes car) really smooth and flat.

In my opinion tuning between 35 and 40 in most cases will get you what you want. The graph should have no sharp peaks or dipps and it will sound good. Also try to keep your relative gain under 3dB.

Just my 10 cents worth

sorry my bad, cant run forced beta cause amp isn't 1 ohm stable- dual 2 ohm voice coils-
and cant quite figure how to show plots on this forum, use yur imagination :)

sorry my bad, cant run forced beta cause amp isn't 1 ohm stable- dual 2 ohm voice coils-
and cant quite figure how to show plots on this forum, use yur imagination :)

Im going to be putting my eclipse 7104d2 in my girlfriends car and am debating what to do for an enclosure. right now its in a .7' sealed enclosure i built, but i was contemplating a vented enclosure. I was wondering what to tune the box to. the fs on the speaker is 33 and i dont know if tuning at lower than that would be a problem. i prefer sq over spl and found that a 1.4' box tuned to 28hz produces a nice flat response, but i'm not sure if i should tune below 33hz or not. i am also debating running forced beta in the sealed box because the amp i have is a kicker 600.1 rated at 750 watts. the sub is rated for 400 rms, but i figure if i set my gains right i should have no problem running the full amp power to the sub in a sealed box. the pics are the gain and spl plots from WinISD. the yellow is the .7' sealed running at 600 watts and the green is the 1.4 tuned to 28 hz. @ 300 watts. Any comments and advice would be much apreciated