Subwoofer box plans drawn out!

phil65phil65 Posts: 24
edited November 2013 in Car Subwoofer Talk
Drew out the plans for my new sub (on the way in the mail). Subs a polk MM1040, box is about .67 cubic feet. The box is going under my left rear passenger seat in my sierra. External dimensions are 18" wide, 7"deep, 14"long at the top and 12" long at the bottom, Building out of 3/4 in mdf. Only issue i might see is that the sub is only going to be about an inch to two inches from the bottom of the seat, is this going to cause any disruptions in sound? I figure I will just fold the seat up when theres 2 people in my truck.
Post edited by phil65 on


  • phil65phil65 Posts: 24
    edited January 2012
    Got the sub and the amp (pa880) in the mail a few days ago. Just purchased the mdf, wood screws, wood glue, and silicon today. Anyway im trying to figure out how to mount the box so it easily removable but well secured while driving. I was thinking about mounting a strip of wood in front of the box to hold it then installing two nylon straps with the pull tight backpack style clips in them bolted to the wood in the front and the floor in the back. What are your thoughts?
  • phil65phil65 Posts: 24
    edited January 2012
    Well not getting much help here. Anyway im considering another option, building and mounting a custom box to sit between the center console and the rear seat, which would eliminate any possibility of a center rear seat passenger unless the box is removed, but would be easier to build (less angled cuts) and mount. Down firing or up firing are also options with that install, anyone going to chime in?
  • 809peter809peter Posts: 16
    edited January 2012
    No much help here indeed.
    I asume you are familiar with the polk box plan site: ?
    If not, take a look.
    If I were you I'd prefer the center position. And make it removable.
    I wouldn't worry to much about the clearance. 2 inches is fine.
    Just be sure nothing touches the woofer.
    Asuming you mount the amp on a different place, make an extra connector (with the female side on the amp!) in the wires to the subwoofer. And don't forget an extra off switch in the remote wire, to disable the amp when running without sub.

    By the way. I've got a MM840 for 2 years now. And I'm still satisfied.
  • SDA1CSDA1C Posts: 2,054
    edited January 2012
    I built a box that fired 2 8's isobaric that sat between the front seats in my Bronco. It was All you needed for the lower mid range. A complementary 12 in the trunk really set it off.

    Sounds like you have a fun project going there. Good luck!

    Sda2.3 (Tweets, Spikes)
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    12" DXi x 2 (Dayton Plate. Slot ported Custom boxes)

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  • phil65phil65 Posts: 24
    edited January 2012
    Considered the center mount option and its just not gonna work without a bunch of complex cuts, unfortunately my dads fully stocked woodshop is 250 miles away and ive got school to attend here. So im going to be working with a buddies table saw, should be able to make all the cuts to get a nice well fitting assembly. Re worked the box size and now have an internal volume of .658 cuft with braces included. Polk recommends minimal polyfill, how much is minimal?
  • phil65phil65 Posts: 24
    edited February 2012
    Built it for under the passenger rear seat, fits perfectly with almost perfect internal volume (within .01 cu ft). If anyone wants plans for this box let me know and I'll happily send them to you.
    Right now the last little bit of silicon is curing around the speaker cable and it will all hopefully be installed tomorrow.
    Once again how much polyfill?
  • 20hz20hz Posts: 643
    edited October 2013
    minimal is just enough to break up interior resonances so thats like a inch or 2 on the walls its a good idea to smear out some glue in there so the polyfill stays put
  • EocuphEocuph Posts: 73
    edited October 2013
    Install a speaker grill/cover, the sub will not be hitting the seat at high excursion. It is perfectly ok if the grill is pushed against the foam of the bottom of the seat.
  • jacksportsjacksports Posts: 4
    edited November 2013
    Well, it makes sense these situations!
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