# Will it be a bandpass???



## hotcress (May 24, 2009)

I prefer rear facing ported enclosers. But I have this idea and want to know if the result would be considered a bandpass type. Basically a box in a box. I want all output to enter the car through the ski hole. It measures 8x12. The sub will fire and be ported to the rear. That rear wall will be removable. The top and bottom panels will be shared by both boxes. The encloser will load the output at the back and send sideways and forward through the ski hole. Trying to avoid rattles and be able to run some comps in the rear deck without the sub's output messing with them. Will this be acceptible if done properly. Oh, the sub is an audiopulse axis 12" (tc 3000) quad coil on about 1500rms. Never figured out the best box size for this thing. So if anyone has any suggestions, please let me know.


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## seagregory (May 18, 2011)

yes it is a bandpass 6th order. If you do it right it should work fine you may wanna seek the help of some others that have experience with the small scale bandpasses. They can be difficult.


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## Chaos (Oct 27, 2005)

No, that would not be a true bandpass enclosure. If I understand correctly, what you are describing is a standard vented (4th order) box with a "duct" that would be used to funnel the output to the pass-through.

Even if that did work, and I'm not sure that it would, you would be losing the gain that typically results from rear-facing enclosures in the trunk of sedans. By impeding the waveform with this "duct" from loading off the back of the trunk, I do not think that you would not achieve the desired effect at all.

Check this out: The Subwoofer DIY Page


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## hotcress (May 24, 2009)

From how im seeing it, the only duct would be the 12x8x3 inch duct entering the cabin. So what your saying is that it won't have enough distance from the back of the box for the wave to fully develope is it would off the rear of the trunk?


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## Chaos (Oct 27, 2005)

Honestly, I don't know that the heck might happen if you tried to "steer" the output of a vented box with a duct like that. I pretty sure that I understand what you are intending to accomplish with this idea, but what it comes down to is that you are over-thinking it.

Just face the sub and the port forward, towards the cabin instead, and you'll achieve the same effect. If you really find a rear-firing design that much more favorable, then either fabricate some enclosures for the rear deck speakers, or take them out entirely.


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## seagregory (May 18, 2011)

lol If you do it like you said and build a box in a box it is a bandpass I am not gonna get to much more into it other than from a spl standpoint the trunk in itself maybe looked at as a bandpass. I have seen it done in old school big bodies with huge trunks for them it works quite well.... You are however over thinking it and I like the advice givin in the second post made by chaos. Even though are opinions differ some I think we would both agree that if you just build a nice forward firing enclosure you will be just as happy.


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## hotcress (May 24, 2009)

I've done front fired before. Dont like it. Love loading off rear. Guess i'll have to dampen the **** out of the trunk. Also, never ran rear fill before. It would be a first. Just want the mids and highs louder sometimes.


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