PURE SPL Box.

[MikeMartel 64]

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.

[jonbearsmt 919]

tune high

[MikeMartel 64]

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?

[///M5 2,833]

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.

[MikeMartel 64]

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

[jonbearsmt 919]

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

[shizzzon 461]

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

[Adrian_D 520]

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.

[MikeMartel 64]

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.

[duanebrow 6]

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

[///M5 2,833]

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.

[Adrian_D 520]

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.

[MikeMartel 64]

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

[Adrian_D 520]

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.

[Adrian_D 520]

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.

[MikeMartel 64]

Sure picture would be cool. Thanks for helping out

[///M5 2,833]

Double seam and stripping ftw

[Adrian_D 520]

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