Ground pounder build. ? on box placement.

[chuey_316 0]

Ok, i've been wanting to build a ground pounder for awile now and i'm getting everything worked out before i start. I've gotten some help on box size and tuning (thank you mark) and now i need to figure out my box placement.

Looks like the subs will be 4 mj-18's run off a power acoustik a3000db in an 18-20 cube box (depends on if i can fit 20) tuned between 30-35hz. Now i can build the box from behind the front seats back to the tailgate and fire the subs up, or i could build it from the tailgate to where the rear seat is at(it's gonna be out or folded) and fire the subs forward.

If the subs fire forward then the port(s) will also. If it would be better firing up, the i'll do that, but i don't know if the port should fire up or forward.

I'm not interested in #'s with this system. Just some good ol gut wrenching, wobbly eyed bass that'll shake the ground, and sound good and accurate doing it. I don't want to be loud, but have my truck sound like a fart can.lol

The type of bass i like. I love bass that kicks you in the chest, takes your breath away, blurs your vision, and can also shake you around a lillte. In other words, hit hard as hell, and be tight and LOUD.

Thanks for any input.

Edited May 16, 2007 by chuey_316

[Aaron Clinton 2,372]

I have found for deeper gut wrenching type bass, give the sound waves the longest distance to travel from them to you. So if you could fire rear ward or upward it would help from my experience, but most of that experience is in an Explorer or other large SUVs.

[mrogowski 6]

I would aim 35-36Hz if you are going with 20 cubes. It will give you that extra authority in the 40Hz range that everyone seems to love...

[JEREMIAH 0]

subs up ports back

[JEREMIAH 0]

O and my mj-18 should be here to day!!!!!!

[chuey_316 0]

How much port area is recommended per sub. I was think 30-40, does that sound about right for what i'm looking for?

I got some of the junk out of the ol lady's blazer and took some rough measurements. Looks like i'll be able to sqeeze right around 20.5 cubes before displacements and still have room to kick back, have my dual battery setup in the rear, and be pretty much right at the window line.

Kinda wanted 4 ports for symetrical reasons, but to keep displacements down i figure it'll be 3 8" ports. That'll give me 150.72 in^2 port area with 37.68 per sub. Not sure if that's enough area or not. My hc has just shy of 100 in^2 port area by itself.

Have decided that the subs will fire up btw. I don't have the patience nor the time to get every angle perfect in order for it to fit the 4 subs front firing, and it just plain won't fit for rear firing.

Now if someones who lives in the sw michigan/nw indiana area want's to come out and help with the box and make that puppy front firng and wall it off, well i'll buy the beer. Got a bandsaw, and recently got a couple laser circular saws, sawzall and whatnot , but got rid of the tablesaw before i decided to take on this project.

Edited May 17, 2007 by chuey_316

[chuey_316 0]

One other question. What's the displacement on the mj-18? Right now after port displacement i'm sitting at 4.8 ft^3 per sub. Bracing won't take up any real noticable space cus i'm gonna use some 3/8 threaded rod, or some angle iron. I'm not even gonna bother factoring that little stuff in.

My last box i factored the threaded rod, as well as the speaker wire.lol It was an abc though and i was pretty anal about it being as close to perfect is i could get it. Even carried like 10 decimal spaces to ensure a perfect 1/3 to 2/3 ratio.

Edited May 17, 2007 by chuey_316

[mrogowski 6]

An option would be to go with two 10" ports rather than three 8" ones. 10's will move the velocity of the ports down in frequency a bit. Plus it will be symmetrical provided you go with one cavity.

Having 4 MJ's will take up about a cube. I calculated two 10" ports at ~0.9 cubes. So you will be working with ~18.1 cubes total. Line the back and two sides of the box with R20 fibreglass any you will add ~10% to the volume of the box. You should be good to go.

POST PICS!!!

[chuey_316 0]

I thought about 2 10" ports afrter i posted the last reply. Now since you brought it up, that's what i'll go for. It'll be awhile before anything gets moving on this. I'm looking into buying a house right now, but i want all the details of this build to be hammered out before i ever start. That way it'll go smoothly.

Thank you for all the help you've given me. I truley do appreciate it.

[JEREMIAH 0]

An option would be to go with two 10" ports rather than three 8" ones. 10's will move the velocity of the ports down in frequency a bit. Plus it will be symmetrical provided you go with one cavity.

Having 4 MJ's will take up about a cube. I calculated two 10" ports at ~0.9 cubes. So you will be working with ~18.1 cubes total. Line the back and two sides of the box with R20 fibreglass any you will add ~10% to the volume of the box. You should be good to go.

POST PICS!!!

? all four will only take up one cube?

[JEREMIAH 0]

O and my mj-18!!!!

[JEREMIAH 0]

I love it think you mark

[chuey_316 0]

That is a beauty jeremiah. Good job on that box as well. Looks like a wedge box, or is it the angle of the pic?

Looks like i'm stuck with 3 8" ports after all. Nobody around me carries anything bigger than 8". It's at a good price though. I think it was something like $5 for 10 foot. unless they put the wrong price on it, but in michigan what it says it what you get it for, so i'm gonna pick some up.

[JEREMIAH 0]

the sub is on a 48

[JEREMIAH 0]

it's 16"H in the trunk so to get a 18" in there I had to put the sub on a 48

[JEREMIAH 0]

O and the mj-18 is $79 to the dor now

[chuey_316 0]

O and the mj-18 is $79 to the dor now

You sure? I just went to the shop and it quoted me $95.79 with the lowest shipping. Maybe it hasn't be changed in the code yet? Stiil a damn good deal though.

If it is gonna be $79 shipped, please let me know, cause i'll start ordering sooner.

Edited May 20, 2007 by chuey_316

[JEREMIAH 0]

http://www.soundsolutionsaudio.com/shop/in...mp;productId=52

[Aaron Clinton 2,372]

There seems to be confusion. But it was a flat rate before at $106 with shipping. But we were able to fix the shipping code issues with our shop software. So now the MJ-18 and MAW-15 might be a few dollars cheaper depending on where you are in the country.

[JEREMIAH 0]

is shipping not included in the price now?

[Aaron Clinton 2,372]

is shipping not included in the price now?

It was, but we got the code module fixed so shipping is not part of the price. Meaning it could save some people a few dollars.

[JEREMIAH 0]