DIY Slot Ported Box Build with 4 Lanzar MAX10D Subs for Project Fit

I finally got some 3/4″ MDF to build the box for the Lanzar MAX10Ds I got so this post will feature my design and a few build photos of the enclosure. It is 5.4cu/ft before woofer and port displacement, 4.4 cu/ft after. This gives each sub 1.1 cu/ft. The box is tuned to 33hz and features a rear mounted slot port, the woofers face up. The port size could be a bit larger but I figured it will do, it is 18.5″ x 2.5″ x 17.75″ long. This leaves about 5″ between the port and the front of the box.

SPL Science Slot Ported box for 4 x Lanzar MAX10D


Rough 3-d sketch of the box


Box layout from a single 4′ x 8′ sheet of 3/4″ MDF.

Box Specs 

  • 24″ x 24″ x 20″ tall
  • 5.4 cu/ft prior to woofer/port displacement ; 4.4 cu/ft after
  • 18.5″ x 2.5″ x 17.75″ long slot port (Rear facing)
  • 4 x Lanzar MAX10D Subwoofers (Top mounted) Wired to 2 ohm final load (DVC woofers in wired series @ 8 ohms, then all paralleled together)
  • 3/4″ MDF 8×4 sheet (didn’t use the entire thing)
  • Elmers Max Wood Glue
  • 2″ Screws (Lots)
  • 1″ Screws to mount woofers. If I had a double top plate I’d use the 2″ but with only 3/4″ no sense using longer than 1″.
  • Total Cost – $96 for 4 Woofers, $33 for the sheet of 3/4″ MDF, $8 worth of Screws, $6 Glue = $143 plus carpet and a terminal cup.


Drawing out the holes for the 10’s. Still just testing fit before mounting anything together.


Test fitting the wood before building.


Woofer holes cut, I currently don’t have a router so I had to do it the old fashioned way with a jigsaw.


Woofers test fit.


Getting some panels mounted.


More progress…


Top view, port on the left.


All screwed and glued, just need to add the brace. (Had to do it old school, but I will get a nail gun for future builds. I forgot how much of a pain it is to do it this way.)


Brace mounted, you can see it in the center of the box. This will keep the top of the box from flexing.

That wraps it up for now. I have mounted the woofers and tried it out but until I can get a terminal cup and carpet it will look as it does above, except with woofers. Videos to come…


  • John says:

    I’m interested in building either ported or 4th order box for my 96 explorer. Which box do you think performed better with those subs? I’m building on the cheap, so those subs would work for me. Any info would be appreciated.

    • admin says:

      The 4th order was way larger but if you have the space it was certainly louder at it’s peak frequency. I also tried 2 subs in the same ported box I originally had the 4 in (4.4 cu/ft) and it matched the output of the 4 even with half the power. It seems they really love air space, so go as big as you can. You will need to be easy on the volume though, they cannot take extended beatings without over heating especially in an over sized box. I liked the 4th order better though, it really got down.

  • John says:

    Thanks for the info. I really want to try the 4th order, I might splurge a little on the subs and get better quality.

  • Scotty says:

    I’m aware that this is an old thread, however I haven’t been able to solicit much response elsewhere so I figured I’d try. I’m installing on my single cab truck, therefore I have little space. Roughly 1.1 cu.ft. per sub. I’m aware this is plenty for sealed application but is it possible there’s enough space there to port or would I do better to go 4×10’s in small sealed space? I currently run Jl Tr 650 CXis in the doors on a 2nd amp along with Kenwood 4×6 pillars. The amp I’ll use to power my subs is a JL xd600/1. I’m sure its RMS is well above 600 but not certain its enough amp. Thoughts? Also any recommendations regarding a 50ish RMS tweet that won’t break my wallet?

    • admin says:

      With only a couple cu/ft to work with I’d rock sealed subs. Just get some really strong ones and feed them as much power as possible for maximum output. If you’re set with that amp just get some super efficient ones. As for budget tweeters, it’s been a while since I’ve shopped but typically the Infinity stand alone tweeter sets are good on a budget.

  • Michael bradberry says:

    I need to do this for 4 8s plz help with the sizes

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