Need box design plans for mojo 12s

[Buck 5,000+ posts]

you're not going to go wrong with a ported box either. what year explorer is it? the different body styles have different resonances and peaks. i had a fairly loud explorer at one time lol

 

[LMJexploder]

its a 94 explorer, i did some measuring and used torres and i would be real tight for a 4th order to fit but i came up with a ported box external dim. 40"x 26"x 17" with slot port 15.5" x 6" at 17" length, 93sq" port area with a 6.2cu feet net
sub up port back. not much smaller than the 4th or maybe i wasnt doing the 4th right but itll fit who needs back seats anyway lol. do those box specs look like they will work? ill be giving them the full 1500w rms i have a taramp 3000k 1ohm amp to power them.

 

[shredder2]

its a 94 explorer, i came up with a ported box external dim. 40"x 26"x 17" with slot port 15.5" x 6" at 17" length, 93sq" port area with a 6.2cu feet net
sub up port back.

I'm assuming you're leaving sufficient clearance for the port?
I always use .75" less on height then slap a second baffle on top when subs up/port back for either 2 or 3 common wall when using Torres myself.

Can you screenshot what you came up with in Torres?

 

[Buck 5,000+ posts]

I'm assuming you're leaving sufficient clearance for the port?
I always use .75" less on height then slap a second baffle on top when subs up/port back for either 2 or 3 common wall when using Torres myself.

Can you screenshot what you came up with in Torres?

When you do that, you need to count the sub cutout radius and do pi*r^2 * baffle thickness /1728 because that adds to airspace, if it's not flush mount. Some of the 4 and 5 layers walls for the you know like 3-4-5kw woofers, like a 16.5" hole that's 5 baffles deep is a significant amount added to box volume.

 

[Buck 5,000+ posts]

its a 94 explorer, i did some measuring and used torres and i would be real tight for a 4th order to fit but i came up with a ported box external dim. 40"x 26"x 17" with slot port 15.5" x 6" at 17" length, 93sq" port area with a 6.2cu feet net
sub up port back. not much smaller than the 4th or maybe i wasnt doing the 4th right but itll fit who needs back seats anyway lol. do those box specs look like they will work? ill be giving them the full 1500w rms i have a taramp 3000k 1ohm amp to power them.

I'd have to check but that seems like too much net unless the mojo's have changed.

 

[Buck 5,000+ posts]

I'd have to check but that seems like too much net unless the mojo's have changed.

If you can OP, see what your group delay is if you do 6 cubes with the mojos and how xmax looks away from tuning frequency. I don't get why they recommend 3.25 cubes per 12. That has to be gross and not net. If I was you, I'd sell them and do 2 15's like maybe Dc's or sundowns or 15's that'll fit in 3 cubes net. If you do the 12's, I think I would try to aim more towards 5 cubes net, or I would.

Further looking at t/s of the 12" mojo6, they look maybe like relatively weak motored. They don't post the Re. Xmax is low too, that may be why they want it in a larger ported box is to try to make it a little more efficient. I wonder what the Xmech is on these. They don't give the Re configuration so their Bl doesn't mean much. Ugh i'm not opening a design program though. You can and look at the Re and Bl ratio. Still seems low to me. You might benefit greatly from a quasi-series 6th order with these. Do a small port area and have some sort of front chamber with some sort of loading wall. Idk if that would even begin to fit in your space. You could do a center port exiting rear and have the subs facing each other inside of the port, right at the exit into the vehicle cab airspace. That'll help with the lower xmax, keep the cones linear.

Hey @shredder2, with 2.1 cubes sealed, what's his Fc/Frc on that?

 

[shredder2]

with 2.1 cubes sealed, what's his Fc/Frc on that?

It was right at tuning... 47hz iirc

 

[Buck 5,000+ posts]

It was right at tuning... 47hz iirc

That's not too shabby. I just think he should switch to some small box 15's

 

[LMJexploder]

shredder2 here is the screen shot and a pic of the box i came up with i added a second piece on the front for strength after i used torres but i didnt think it will change anything, or will that not work. i still need to add some bracing inside the box that i know. Also , yes i did leave room between box and rear door about 6-8 inches. or should i leave more

 

[shredder2]

That drawing looks good above, maybe brace the side panels to the port walls with some window bracing instead of worrying about bracing the smaller front panels.
Jmo
I agree on others opinion regarding the subs suitability in a ported alignment, I'd personally go a bit smaller volume wise and think 5ft3 net 80in2 of port would be more than enough for those subs.
However a 3K at 1 ohm is NOT going to deliver 3K once installed so the oversized box should be a wash to make up for any driver limitations without killing the subs.
The Ebp WAS a little low Iirc and that usually screams weaker motor strength. Hence the 4th recommendation.

 

[LMJexploder]

ok so should i keep it the same size and add the bracing with the 3k amp or lower it to 5 cubes net with that amp

 

[shredder2]

I can't know your goals, but most people nowadays like a lower tuning than around 37hz... why not shoot for a lower tune since you got the space?.. whatever you end up with volume wise I'd personally not worry about overpowering those subs as the volume will be less in the same footprint with a sufficient longer port. Just keep the port 12-16in2^ft3 or thereabouts

 

[LMJexploder]

ok ill keep messin with it, i appreciate your help and pointers thanks again

 

[Buck 5,000+ posts]

ok so should i keep it the same size and add the bracing with the 3k amp or lower it to 5 cubes net with that amp

What you may want to do is look at what memphis recommends for their port- you can calculate their cubic footage of port it takes up and subtract it from the box size they recommend, and see what that number is.

 

[Buck 5,000+ posts]

and if you're listening to rap, i would tune at 32-34. like if you want musical bass, you can do closer to 10-12 in^2 per cube. you may want to download winisd or something, to see what your port air speeds look like.