mx-3 box

[thumpinmx]

Hi I am building a box for my brothers mx-3 as a xmas present... but I need to know the dimensions I have to work with... i dont want to ask him cause he will know what I am doing... want to keep it a surprise....
So what I need to know... is what is the widest i can build the box and max height so he can still see out the rear window.... The rear seat are removed already so no big deal on depth.....
Thanks in advance.....

[xxwhiteboyjim22xx]

Depends on what you want to put in the box?

[thumpinmx]

i know what i am doing
sundown saz-3000d powering a 15" full loaded BTL..
Just need the max width and height

This is something i designed but not sure if it will fit.....

[chew*]

First off up fired, ported rear will be an epic fail in that particular car. The box needs to be mounted tight against the back seat and not extend over the edge of the spare tire well. I't look like your rolling ported so............the port will need to be fired rear as well as the sub. It looks like your slot porting so I will let you in on a secret. Since you will have limited dimesions and the box will need to be wide and shallow you will have an issue tuning it. The secret is you can fold the port. Etc you can run a 8" long port then do a 90 degree turn and continue on with the port. It will have no effect on performance whatsoever.

The resonant frequency of the car is 52hz, so if you tune for around 25-30 hz it will slope down and then slope back up around 52 then taper off again.

[Ryan]

chew*, I think you lose most people

[thumpinmx]

chew do you mean like this? also was thinking to tune to around 35hz any tips are more then welcome..... or just a normal L shapped port?

[chew*]

That will work also but just continuing the original port to the right will work better. I don't have a program like that but i'll do a quick and dirty one for you. If you end up running a preety hefty sub however you may have to use the design in your second picture to allow for the magnet/motor of the sub. If you angle the back of the box a tad you can gain a little more cubic volume if needed but angles complicate construction somewhat. Hopefully someone can give you exact dimensions as my car is in a storage unit for the winter already.

[thumpinmx]

that is the way the first one is... just a normal L shaped port.... just have to rear fire the sub also....
check your pms

[chew*]

chew*, I think you lose most people

Yah that comes from being in the spl scene to long, It tends to make you take a more technical approach, takes alot of fun out of it but after building X amount of boxes for a car the technical approach can cut it down to maybe 3 builds. When you build a wall you really only want to have to do it once.

[thumpinmx]

yeah the sub is very beefy... will be feeding it 3000w rms +
Can i remove the back seat cause that sub works best in a 4cuft box after sub and port displacement.... I dont think by keeping the back seat in there will give me enough space....

[chew*]

yeah the sub is very beefy... will be feeding it 3000w rms +
Can i remove the back seat cause that sub works best in a 4cuft box after sub and port displacement.... I dont think by keeping the back seat in there will give me enough space....

By all means remove the back seat. If its going to be that extreme You will definitely need measurements. You will need to measure from the edge of the tirewell closest to rear seat to the back of the car, you will want the depth of the enclosure identical. This will couple the box with the hatch turning the hatch into what i like to call a false wall. This is exactly how I managed to hit 159db ( save it was tuned to 52hz ). It turns the hatch into a virtual port.

[thumpinmx]

ok added you to aim sign on when you have a few minutes if you dont mind... i have a few questions for ya...

[thumpinmx]

Do you mean like this?

[chew*]

Yep thats perfect if you run into the box being a little to much volume you can just make it narrower, it won't effect anything.

[thumpinmx]

Thank you Chew for all your help i really appreciate it.