15in Sub Plans

[MCP1991]

So I designed and built this sub for my new festiva and thought I may as well post the plans here for anybody else who wants a nice big sub.

It's a LAB15 driver in a 3.3cuft box tuned to 33hz, max SPL is around 120db, and I'd recommend an amp that can do around 600-1000w at 4 ohm.
This particular driver was a 4 ohm version of the LAB15, if you use the 6 ohm version you'll need an even more powerful amp to get the voltage it needs.

I designed it to replace the back seat, it bolts down using the front-side rear seat mount bolts with L brackets, and I'd definitely recommend bolting it down because you don't want this flying around in a crash or something.
You may have to drill holes in the floor to bolt the back side of it down.

I used plywood in the build because it's lighter and more durable than MDF, and weight is an issue with a box and driver this big, IMO at least.

Tips for assembly, use a nail gun with 1.25in nails to hold everything together as you go, this way you can get it all done without waiting for any of the glue to dry.

Glue, clamp, nail, remove clamps, move on to the next joint.

As for glue I recommend loctite PL premium, it's super sticky and messy but it's the best glue for making speakers IMO, it expands and fills cracks so you don't have to worry about leaks and your cuts can have more slack in tolerances.

Don't try to wipe the glue off before it dries, the stuff that squeezes out of the gaps can either be scraped off carefully when wet or it's best to wait a bit then use a scraper to take it off.
Trying to wipe it off is just going to make a huge mess and you can't remove the stuff with sand paper later, it just doesn't sand down.

I like to leave a slight bit of overhang on all the corners where the wood meets up, then use a flush trim bit on a router to bring it in clean and flush.

I've included the winISD model of the enclosure for this driver, the cutlist in PDF format and the sketchup file so you can look at it before building.

I ended up not installing the cross brace below the driver, just be aware that you shouldn't block the pole vent on the back of the driver and keep driver depth in mind.

Pics of the build: http://imgur.com/a/iIYQf
Cutlist, windISD and sketchup files: https://u.teknik.io/BPmEYg.zip

[william]

Looks awesome ,wish I had your box building skills.
Great job. First link works but couldn't open the 2nd.

[bravekozak]

And I thought this thread was all about converting a Festiva into a homemade submarine to travel underwater. I didn't realize that Arizona had a Navy.

Wouldn't it be easier to just change your center console?

Wouldn't a stock 8" console be enough? Then you still have all the space in the rear.

If not, then how about an in-seat subwoofer?

Do you think the Wrangler subwoofer can fit behind the rear plastic?

[MCP1991]

That's weird, it still works for me.
Try this https://mega.nz/#!3pwXHSTL!IvXHtMUW_...VgDV9v_6fe5W4s

Building a sub box is pretty easy honestly, the hardest part is getting all the cuts straight and dead on measured.

To bravekozak, the center console sub wont be able to go anywhere near as low or loud as a ported 15, sealed boxes are very inefficient, and it being an 8 inch driver isn't helping either.

When it comes to making low frequencies, the bigger the speaker the better, you need as much surface area on the cone as you can get (within reason, you don't wanna turn your entire car into a subwoofer)

In-seat subwoofer could work well as long as it's sealed well.
If it's just a hole in the seat with a driver bolted in and not actually a box, then it's not going to perform very well, you need a tight seal to keep the back wave from interacting with the front wave.

That jeep console sub would work for a bit of thump but don't expect too much, also that one you linked is cracked, being a sealed design you can't have any air leaks, and that's most definitely an air leak.

It all depends on what you're after, if you just want a little help for the speakers to go lower, those small subs you linked would be fine, but if you want really loud you need a big box with a big speaker, it's just a physics thing.