Printer Friendly Forum Posts - single cab blow through

i mean like where do i get the material? and you had helped me on my last post on figuring my box size. i am new to the SPL world ive done some installs where they were mainly for looks now im trying to get some more serious bass out my personal install. Ive got 1 mofo and a PA 2000D and it just isnt impressing me its loud but not loud enough. Im thinking of adding another mofo and another 2000D but do you think i can get a big enough box in there without a blow through? And could you help me with my box design ?

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First major build for myself in the process

I have no problem helping with box design. Sorry i miss read your post. I thought you were asking, why you would seal it. We used to get the seals from a truck accessory store. They sold camper shells and such. We called it boot seal. It was about $5 a foot. Mind you the last time i did one was in '99 when i walled out my Nissan hard body with 8 15s. I miss those days :)

On the subject of adding another MOFO. I would honestly use the one you have now for a paperweight over a sub. Same for the amp. There are much better products out there at a reasonable price. Also how serious are you about SPL? What is your goal? If your are wanting to build a SPL comp system to compete with. Knowing the organization would greatly help for the class you wish to enter. If this is a daily beater. Tune and such would be different to be better to listen to.

Also with the figures i got on your current enclosure. Your tune is pretty high. It's basically a burp box. Better to pull numbers in a lane, but it will be lackluster for a daily listening environment. Not to mention sound pretty bad. Simply by putting it at a lower tune might help you quite a bit.

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ok its a daily beater but i want some good bass. im thinking its to small they ask for 2.4 cube ported for that sub. I know my equipment isnt the best lol but i got the sub and amp for 150$ i couldnt really pass it up. i know what you mean by the burp thing cuz it really only sounds good on real deep bass songs which is hard to find. I would appreciate it if you could help me design a box for just the one and amp i have now like i said its a single cab but ive got a 10" deep box behind the seats now and can go more (i'm only 5'4" tall lol) plus ill have a good box build when i can afford to upgrade my equipment i think a blow through is taking it a little far. Im kind of a newbie to making something loud like i said ive done alot of just good looking installs fiberglass boxes mostly

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First major build for myself in the process

also anothe thing i forgot to add is my port now is a slot port going forwards towards my seat is there a better way to port it like going towards the roof? Im sorry for all the questions man im just really needin some help here and i'd appreciate any advice you can give me i just want to get maximum out of what i have.

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First major build for myself in the process

Is this your sub? MOFO

If it is then your current airspace is bigger then recommended. It should be 2.0 cu.ft. GROSS and your port area is way too much. They call for a 4" round port. Thats only 12.56 sq.in. of port area. The slot port you have is 25 sq.in. of port area.

Im a bit confused because you said you had a Memphis Mojo before and then you said MOFO which is a power acoustik sub.

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yea the mojo was a long story i showed up to buy it and the kid had a power reference 12 so i instantly laughed at him and left lol then i stumbled accross the mofo, and yes that is the one i have. well i already plan on building a new box so can you help me with a rough estimate of dimensions. my max height is 13.75 cuz of a cross member in my cab max depth i wanna go is 12. port size i understand but which way should it be facing out of the top?

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First major build for myself in the process

Well the biggest thing for the port is to not block it. if say your port is 2 inches wide. You would want at least 2 inches from it to a wall, seat back ect. Being limited on space you may want to port it out the top. I need to get a bit of sleep now. I will punch in some figures when i get up tomorrow. I have your dimension for you current enclosure. I will work from those to give you the optimal enclosure for your sub from that. We may actually be able to save the enclosure you have. It is a bit larger than needed. Pretty easy to take away space inside. Would just need to block up the slot port and run the proper port.

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alright yea i appreciate it man just let me kno whenever you figure it out. Try and give as much detail as you can about the port on which way it should face and all the clearances and dimensions. Thanks again man like i said im new to the SPL side of things ive worked at a little shop around here doing installs but i never built the boxes we had another guy that did just that i did the actual install wiring and did the pretty looking stuff lol

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First major build for myself in the process

I did not take the time to read to see if you got your answer yet, if not, you need to go to a camper supply store and look into an "Accordian style camper boot seal" You can use the search function here, I have mentioned it here once or twice.

When cutting the holes, you need to cut the hole in the bed 2 inches larger in the bed than in the cab of the truck. 10 x 22 in cab = 12 x 24 in the bed of the truck. This is NECESSARY to accomodate frame flex, the bed needs to be able to flex independent of the cab. Mount the box to the cab and have only a support in the middle of the bed.

so j. reed did ya come up with anything for me yet?

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First major build for myself in the process

Yeah I came up with.

37.25"W x 13"H x 10" D. 2.02cu.ft. GROSS Port 4" round x 14" long Fb 33Hz.

Gross volume 2.02cu.ft.
- port .10
- driver displacement .15
NET= 1.77cu.ft.

Or if you want to stick to the recommended enclosure and tune.

37"W x 13"H x 10"D. 2.0 cu.ft. GROSS port 4" x 12" Fb 36Hz

Gross volume 2.0cu.ft.
- port .08
- driver displacement .15
NET= 1.77cu.ft.

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ok so that should make it louder right?and r those outside dimensions, and which way should u put the port, and for a round port use PVC pipe?

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First major build for myself in the process

I've definitly deciced that my second career will be as an audiologist. It'll be like takin candy from a baby.Make that MANY babys.

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"That'll get ya 10 in Leavenworth,11 in Twelveworth, or 5 & 10 in Woolworth". Groucho Marx

hmmm...since ive getting the advice for free, that would be a very unrewarding career.. posted_image

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First major build for myself in the process

Bubba, ya missed the whole point.

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"That'll get ya 10 in Leavenworth,11 in Twelveworth, or 5 & 10 in Woolworth". Groucho Marx

singlecabslamin wrote:

ok so that should make it louder right?and r those outside dimensions, and which way should u put the port, and for a round port use PVC pipe?

It should sound better for sure. Your box now has way to much port area and is too big.

Yes, those are outside dimensions with 3/4" material. You will have to port it out the top to be able to get you port length. Yes, you can use PVC. If you would rather i can figure it in a slot port.

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well what do u recomend lol since it will goin out the top will it sound better? and how do i put a 14" long port in a 13" tall box?

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First major build for myself in the process

oh yea and mrarff, i think i did miss the point lol posted_image

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First major build for myself in the process

ok i am confused now on why you would re-post something i said in a thread i started

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First major build for myself in the process

singlecabslamin wrote:

well what do u recomend lol since it will goin out the top will it sound better? and how do i put a 14" long port in a 13" tall box?

By doing whats called "folding" the port. Simply run a 90 degree bend on the port to extend it. Giving you the extra length needed. Square or round wont make much a difference. The port area per cubic foot is what is important.

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berzina123 wrote:

also anothe thing i forgot to add is my port now is a slot port going forwards towards my seat is there a better way to port it like going towards the roof? Im sorry for all the questions man im just really needin some help here and i'd appreciate any advice you can give me i just want to get maximum out of what i have.

To moderator: This berzina123 guy has 5 posts. All of which are a copy and paste of a previous poster from which ever respective thread they are in.

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ok what about having 2 4" rounds ports that r 7" each since my over length is suppose to be 14"?

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First major build for myself in the process

singlecabslamin wrote:

ok what about having 2 4" rounds ports that r 7" each since my over length is suppose to be 14"?

No, because then you are doubling your port area and raising your tune. Not only by the added port area, but the shortening of the length. You need to "fold" it by putting a 90 deg. Bend in it. Pretty simple, just run say 8 inches down, put a 90 deg bend in and extend it the other 6 inches to make a total of 14 inches. It's not rocket science. Just measure at the center of the port.

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ok i understand that with a slot port but a round port like that had me confused, how do i connect it? i feel like quite the idiot but i swear im not lol just new to ported boxes. like i said ive done tons of simple installs, sealed boxes, and fiberglass enclosures the whole tryin to make numbers thing is new to me

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First major build for myself in the process

90 degree pvc elbow
You can get it at any hardware store.

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posted_image

thats what i figured lol im just trying to decide what i wanna do and i hate to break this to you after all the calculations you've done for me but ive got the older mofo and the specs i found call for a 2.4 cubic ft. box

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First major build for myself in the process

send me a link to the spec sheet. Both the mofo 12 and 122x use the same enclosure volume. 2.0cu.ft.. so im wondering where you are finding this info. Those are the only 2 they have made that i know of.

mofo 122x specs
2700 watt 12" monsterous subwoofer
RMS Power       :1200
Size of each subwoofer :12"
Fs        : 37.28
Qms     : 5.425
Vas      :0.859
Xmax mm          :21
Xmech mm        :31.5
Qes      : 0.744
Re        :3.80
Znom    :4
BL        :16.807
Qts       : 0.654
SPL      : 84.164
V.C. Size (in.)    : 2.5
V.C. Imp           :DVC 2
Cut-out :11.25
Depth    : 6.5
Sealed :1.50
F3 Hz   :43.00
Ported   :2.00
Port      :4x12
Tune Freq. (Hz) :36.16
F3 Hz   :29.18
Cloth/Paper Composite Cone
Blue Cast Aluminum Basket w/ Diamond Cut Accents
Chrome Back Plate
UV Coated Foam Surround
One Piece Rubber Gasket w/ Color Matched Inserts
Dual CONEX Spiders
Nickel Plated 8 ga. Compression Wire Terminal

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https://www.poweracoustik.com/SUPPORT/MANUALS/PA-MOFOWoofer.pdf

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First major build for myself in the process

42"w x 13.25"h x 10.25"d 2.41cu.ft. Gross (2) 3" round ports 6.75" inches long. Fb= 40Hz this would be a SPL box. Will be about as much as you can get numbers wise out of this sub. It will not sound good at all though.

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