Box size for 2 MJ18M

[wasted911 0]

Alrighty,

I got one of my MJ-18Ms back and now I'm looking to make a box for them for the mini-van. The dimensions I have to work with are 45" wide, 48" deep, and 22" tall. I'll be tuning hopefully no higher than 31 or 32 hz. These will be powered by a memphis 4k. I need to get a box designed by tomorrow morning when I will be starting the build. I have only one day to get this box done, so hopefully all goes well. Subs will be facing up, and I'm guessing slot port to the back. Any suggestions at all? I should have 24 cubes before all displacements at that size, but I'll probably shrink it down. It all depends how well things work out. I will have no time tonight to think about a design either as I'm heading to AC/DC in about ten minutes.

Thanks ahead of time.

[mrogowski 6]

5 cubes net tuned to 30Hz.

Inside dimensions:

19"W x 38"L x 14"H

Port - Rear Facing:

3" x 14" x 21"L

Nice to hear from you. I assume you are back in the game again?

EDIT: Didn't see the '2 MJ-18' thing. So go with 10 cubes net - 37"W x 38"L x 14"H and a port of 5" x 14" x 15"L.

[jcarter1885 995]

5 cubes net tuned to 30Hz.

Inside dimensions:

19"W x 38"L x 14"H

Port - Rear Facing:

3" x 14" x 21"L

Nice to hear from you. I assume you are back in the game again?

EDIT: Didn't see the '2 MJ-18' thing. So go with 10 cubes net - 37"W x 38"L x 14"H and a port of 5" x 14" x 15"L.

Thats real professional of you to come on here and give him a design for a box, I like your style. Keep up the good work and cant wait for IXL in dual 4 ohms.

Edited August 25, 2009 by jay-cee

[wasted911 0]

5 cubes net tuned to 30Hz.

Inside dimensions:

19"W x 38"L x 14"H

Port - Rear Facing:

3" x 14" x 21"L

Nice to hear from you. I assume you are back in the game again?

EDIT: Didn't see the '2 MJ-18' thing. So go with 10 cubes net - 37"W x 38"L x 14"H and a port of 5" x 14" x 15"L.

that small for that tuning? Also, I may be able toget my hands on one of the other MJ's that I picked up, so this box MIGHT have to house three woofers.

**Edit

the third woofer wouldn't be added for a while yet, so I wont worry about that. Also, after doing some calcs,it looks ike with the info you gave me (assuming that the subs are .25 cubes each), the net volume would be just under 11 cubic feet, minues the braces.

Edited August 25, 2009 by wasted911

[wasted911 0]

well I got the box done, it sounds great although I do wish the MJ's could take a bit more power. I did also finish to find out THE the sub I just recovered has a mechanical problem. Sounds like the VC isn't aligned properly. I've had a guy repair a speaker before with the same problem so I'll just bring it to him as well.

[mrogowski 6]

Of course it sounds great. Would I steer you wrong?

Let me know what happens.

[wasted911 0]

Of course it sounds great. Would I steer you wrong?

Let me know what happens.

So I brought the one sub in to get fixed and left the other sub in the enclosure and hooked up, asuming that I would hav a bit of low-end to go with the front stage only to find that before I even put the one sub in the box, I burnt the v/c leads.

So apparently I was only rocking the single 18" while the other was floppin around. So I hacked the one back together, and I got the other picked up today as well and she's good as new. So This evening I should have some pictures and videos for all the internet people in here. Next step is getting the second battery in the back and running a whole lot of 2/0.

[wasted911 0]

Well for a bit of an update. We got it on the mic today and pulled off a 146.77 at 45 hz. Keep in mind that this is with a stock battery, stock alt, no big 3 done, and a single run of 4 gauge. Got the amp clamped at 1850 watts at 2 ohms. Once the rest is done we should have no problem doing anywhere between 2200 and 2500 watts. Not bad for an amp rated at 2000 even. Also some new boxes are in the midst of being planned. SS NW here we come.

[mrogowski 6]

Don't expect massive numbers from these units. That's not what they were built for. Quality of sound first, and if they get loud for some people then great, that's what I call a fringe benefit.

Best,

Mark

[wasted911 0]

Don't expect massive numbers from these units. That's not what they were built for. Quality of sound first, and if they get loud for some people then great, that's what I call a fringe benefit.

Best,

Mark

I'm not expecting to get massive numbers from these. I WILL get some big numbers with them. Whether or not they hold up is something I'm really not worried about yet. Once they go I will be replacing them with a different brand of woofer (no offence), and be going off of that. I have DB Don near by so we plan on having some fun. More than likely I wont be at the stage of needing new woofers until spring, but that gives me a lot of time to test.

I think it's official. The bug has bitten me again.

[wasted911 0]

seeing as winter is coming very soon. I got ready for the long haul. I wasn't happy with the LOW lows on this box so I added quite a bit of port. As most SPLers say, build first, then test. I added on the full front length of port (making it an "L"). Apperently it's tuned to about 17 hertz now. It still doesnt seem nearly that low, but it's much more suited to my tastes. Reminds me of the home theatre box I made long ago. Also getting closer and closer to getting some electrical upgrades done as well. Stupid me and switching jobs.

On that note, I will now be an employee of Visions in the CA sales department.

[mrogowski 6]

Good for you. Perhaps Visions will actually sell some car audio now haha.

[wasted911 0]

more bad news. After I got the one sub fixed from the v/c being un-alligned the guy that fixed it probably didn't clean off the basket very well or used a shitty glue. The spider has now let loose and I'm back at step one.

God damnit.

[wasted911 0]

Alrighty. I'm now all fixed up and ready to go. If anyone is in the area feel free to let me know and will gladly demo it. I am currently planning on getting one of the other 18"s back as well and fitting it in somehow.