Porting Box Through Arm Rest Hole

[blownengine]

I'm trying to help a friend out on this one. He has two 12's in the trunk of his Buick. The PROBLEM is that his seats don't fold down

So all the bass gets trapped in the trunk and it sound like he only has a single 8 or something back there.

I have seen people port boxes through the arm rest hole and I'm thinking about building him a box like that.

So my questions are:

1. Would it get louder? (I know everyone hates this question, but really.)

2. Will it sound like crap? I have heard it sound bad because all you hear is port noise and because the bass you hear is from the backward motion of the sub, so the bass always hits a tad late.

Thanks guys

[Red-navi-916]

I have done it in an impala with 2x15s and meterd a high 145 off of a audiopipe 1800watt amp a while back, works out at times other times it doesnt

[hdorre]

Dan, why don't you cut up his car and let us know?

Lolz, jp. Theoretically it'd hit higher on the TL. Idk how practical it'd be for a DD

Edited April 25, 2011 by hdorre

[blownengine]

Dan, why don't you cut up his car and let us know?

Lolz, jp. Theoretically it'd hit higher on the TL. Idk how practical it'd be for a DD

Your right. Let me go grab my saw.......

I don't even know where to got metered around here. This is all off the ear meter.

And he has 2 kicker comps. They sound bad in the first place, so there probably isn't much I can do for sound quality.

Edited April 25, 2011 by blownengine

[hdorre]

Have you considered a 4th or 6th order? If you port that through the armrest, I'm sure it'd be fine.

[blownengine]

Have you considered a 4th or 6th order?

Never build one before. But I have built a good number of boxes so making it wouldn't be a problem.

What would be the benefit besides a straight port into the cabin?

[blownengine]

Ok so I have done some research and I think I will do a 4th order ported through the armrest. I have never built a 4th order before so can someone check my specs?

The subs are two Kicker Comp 12's powered by an Alpine MRP-500

I'm thinking 3 cubic feet in the ported chamber. Tuned to 45 hertz

And 1.5 cubic feet in the sealed chamber.

So thats a 2:1 ratio.

Are my designs correct?

[hdorre]

Have you considered a 4th or 6th order?

Never build one before. But I have built a good number of boxes so making it wouldn't be a problem.

What would be the benefit besides a straight port into the cabin?

Estimating efficiency, frequency response (flat vs peaky), bandwidth/range, and a few other things would be easier. My favorite thing is that you could get the LOW lows without sacrificing the higher frequencies.

As for your design- I cant help ya there...im still new to this myself The tuning frequency and ratio look good to me though. Idk how big they should be.

Keep in mind that the ratio could be varied for different goals

Edited April 25, 2011 by hdorre

[blownengine]

Ok I called up Kicker and here is what they recommend:

Sealed chamber: 1.3 cubic feet (per sub)

Ported chamber: 2.7 cubic feet (commen chamber)

He however recommended tuning at 55 hertz where my original thought was 45.

I want this box to hit the lows really well. Which should I tune to?

[bumonskateboard6]

In 4th order the tuning of the box is not isn't really chosen by the builder it's mostly chosen mathematically. Determine what frequency you want to be your "roll-off" where the subs will stop responding well.

Use this calculator and enter driver parameters:

http://www.colomar.com/Shavano/4thorder_info.html