Alright guys, im in college for Mechanic Apprenticeship and one of my courses next semester is Electrical Accessories, Guess what we get to build! A sub box, Considering i already have a daily box for my BTL 18, i was considering building something for pure SPL if i ever want to try out a competiton..

Anyways, i was just curious from your experiences what platform is the best for pure spl builds, just a basic slot port, 4th order, 6th order ect. (This will be in the trunk so no walls.)

Once i get some information about this ill sit down and see what i can come up with.

tune high

Yeah well iv deffinatly heard about that part for sure, tune high, close to the peak tuning of your vehicle, which im not sure of yet, But i was wondering if a certain type of box would prevail over another type?

Definitely not a 4th order BP, but between the 6th and the reflex you'll be splitting the hairs of how well the design fits your space. I would argue that it would be beneficial for you to attempt this with at least three boxes and measure/feel the difference to truly start to understand what is happening. I'd choose the same alignment for all three.

Alright awesome stuff. We will see what happens, A 6th ordder will be super interesting with my sub needing to face up...

i would not think you have any where near enough space to do a 4th or 6th. unless you wall. with that single 18

eh.. if the 18 is the sub of size.. ANY BP option will not be efficient in a trunk as a standard ported box would be stressing for efficiency as is already...

there is a HIGH probability in my opinion that a 12" sub in a 6th order in a decently large trunk could "potentially" prevail over the standard ported designs.

Not saying it will as that's user trial n error testing but the potential is there...

Maybe even a 10 would be better.. but i'm blabbing with speculation so off you go with testing

For ease of tuning, I would definitely stick with ported. And given you have a trunk car, build everything facing forward (port and sub) and seal off the trunk for best results.

Ok i guess reflex it is then. The only sad part is that i have no time to do the best possible thing for spl which is test and fix, test and fix, ect. Just thought id try something i could actually use since i need to build one anways.

I'd think a removable port would be in order. That way you only have to replace the port to change tuning. Not having to move a huge box would help out - at least on your back

You could also build it with a removable back wall so that you can change box size as well. Figure if its for a class some experimentation is in order.

Ok i guess reflex it is then. The only sad part is that i have no time to do the best possible thing for spl which is test and fix, test and fix, ect. Just thought id try something i could actually use since i need to build one anways.

The hardest part I've found is to get a meter. Once you have it and you can keep the box in your car, you can test whenever you have the time.

I agree with removable port and removable back for a change in volume.

For the port you could also use a round port, have it as far back in the enclosure as possible and just add length on the outside when you need to lower the tuning.

How do you actually design a removeable back that will seal properly? That seems a little confusing to me

One older method I've seen was to have a double back, one panel fits over the box, the other fits between the panels. That had good results.

I'll take a picture if it's not very clear.

You can also use weatherstripping at the joints.

One older method I've seen was to have a double back, one panel fits over the box, the other fits between the panels. That had good results.

I'll take a picture if it's not very clear.

You can also use weatherstripping at the joints.

Sure picture would be cool. Thanks for helping out

Double seam and stripping ftw

I hope that clears it up. Never had problems with air leaks but it wasn't a big box and power was very small.