# blow through box build help



## 88supercharged

i got 2 memphis mojo 12s i need to put in a box. i want a slot ported box with the slot in between the subs. problem is, i have no clue on tuning,hertz,or any of that. i want deep low bass and i listen to rap. the space im working with is 15.5"h 50.5"w and 20"d can anyone help me get started i got an empty hole behind my seats!


----------



## Chaos

Wait... what kind of vehicle do you have? (A blow through typically refers to cutting out the back of a pickup cab, and placing the enclosure in the bed.)

Incidentally, that is roughly 7.3 cubic feet net, which is plenty for a pair of vented 12"


----------



## 88supercharged

yes sir i have a 93 s10 with the hole cut out for a blow through. i figured that was enough air space just not sure exactly how to build the box. i just need to know the size of the ports to get the right sound out of the mojos.


----------



## The real Subzero

88supercharged said:


> yes sir i have a 93 s10 with the hole cut out for a blow through. i figured that was enough air space just not sure exactly how to build the box. i just need to know the size of the ports to get the right sound out of the mojos.


 we need total dimmensions and post pics.



most blow through boxes are like a band pass. do you need a new design? Sounds like you do. 

list the sub your using and amp, what impedance at what power?

what is your goal? spl, SQL,
Do you like it super low? musical.? hard hitter?


----------



## 88supercharged

alright im runnin 2 memphis mojo 12s dvc 4 ohm with 2 memphis 500d amps at 2ohm. my goal would probley be spl since i like deep bass. the measurements i posted in the first post are the dimensions i have to work with. im open to any ideas. i will post pictures after work tomarrow. im also curious to know if anyone has ever heard these subs in action cause i bought these new and ive never heard them action and do i have enough power? thanks for the replies.


----------



## The real Subzero

Depending on which sub you actually have, the dims you gave come out to 7.3 cubes before any displacement. And that is twice what you need. and if you do a bandpass box in the bed and port it into the cab, that is possibly still too much air. I am goinng to assume that your using the lower end subs because the amps you listed ate like 250 nominal at 2 ohms.? yeah? I think you should just put a box in the cab untill you have different subs and amps. to deem it neccessary to to a blow through.


----------



## chapdawg1971

Yeah, but a 4th order can get loud on very little power.


----------



## BuickGN

88supercharged said:


> alright im runnin 2 memphis mojo 12s dvc 4 ohm with 2 memphis 500d amps at 2ohm. my goal would probley be spl since i like deep bass. the measurements i posted in the first post are the dimensions i have to work with. im open to any ideas. i will post pictures after work tomarrow. im also curious to know if anyone has ever heard these subs in action cause i bought these new and ive never heard them action and do i have enough power? thanks for the replies.




Nothing wrong with wanting SPL but I wanted to clarify that you can have deep bass in a non "SPL" system. Many of the SQ cars I've heard including my own hold their own in the really low frequencies.

Check out this thread for some really good info. http://www.diymobileaudio.com/forum...remerevolutions-sub-box-modeling-service.html


----------



## 88supercharged

well i have the mojo 12s that handle 1100 rms and 2 memphis class d amps runnin 500 watts at 2ohm each not 250 watts each. i would think that would be pretty loud but the 12s are brand new so i dont know what they sound like. i guess i have to break them in so if anyone can give me some advice on that i would appreciate it


----------



## The real Subzero

I suggest posting exact model #'s of all the equipment and exact dims of ideal box. and even post photos. 


To be honest, I see a major potential for danger. Because your trying to get loud on half recommended power. and your wanting to use a band pass type box that may hide all signs of clipping. thus, you have a major potential to cook them coils before you ever get a real chance to see what those subs can do. 

If you want to break them in, I suggest a ported box in the cab. and I also suggest you find a oscope and dmm. run some test tones at 50hz and set the gains just below clip point. Then later when your ready and have a design for a bandpass box, build and test and then set the amp gains the same way.


----------



## 88supercharged

these subs are huge i cant fit them anywhere inside the cab so thats not an option and ive been told 500 watts would b good to break them in.


----------



## 88supercharged

i actually have 3 memphis 500d amps. is there a way i could hook up three amps to two subs? im guessing not but that would b 1500 watts rms between two subs


----------

