I am building a fiberglass shoebox type subwoofer for my Insight. I came across John Waylands design and decided to make it bigger and better if possible. I decided on fiberglass as my material to use every cubic inch of space available. I made a cardboard box to fit the space like I wanted and covered it in fiberglass. Several layers and several days later I now have a box that fits the space,is very strong and has more air space inside than any previous subwoofer that fits in the same place. My internal air space is 1007 cubic inches. To get this volume required me to make a complex shaped box not possible with wood. Also the wall thickness is thinner than wood which gained more space as well. I ended up with 3/16 wall thickness after 6 total layers of fiberglass cloth. Here is a picture of the box during the construction.
Last edited by Expertfabricator; 06-20-2009 at 02:20 AM.
Here is the erea the woofer mounts in. The woofer I designed this box for is the Square Kicker L5 which is very heavy duty and more like a 9 inch woofer than a 8.
What some of the pro speaker designs also use, is internal baffling that essential connects opposite walls together, to keep side wall flexing to a minimum.
The baffling does not take up much volume and adds to side wall stiffness, which improves sound quality immensely and keeps weight gain to a minimum.
Any speaker cabinet having relatively thin walls can gain quite a bit of sound quality by utilizing this technique.
Im not sure any bracing will be needed. It supports my weight (175 lbs.) without flexing a bit. In order to play music load enough to make this box flex you would have tons of rattles inside the car anyways. Also due to all the angles and weird shapes involved there isnt any large flat panels really big enough to flex. The 3/16 thick fiberglass sounds thin but thats very strong and made from mat not cloth which is tough stuff and strong in all directions. Fiberglass cloth is only strong in opposing directions to the weave pattern. Im also switching to epoxy resin which is even stronger because Im tired of the fiberglass fumes and the epoxy is better for our planet,but more expensive. I am now making the mold and waiting on the epoxy to cast my first box sometime later this coming week. I also have the box completely finished and glass smooth painted light blue but am having trouble loading pictures lately. I also got the woofer in the mail and let me say this thing is impressive! Its one of those kicker square L5 woofers. I went with it because it had specs to work in the air space I had available and pretty impressive FS,free air resonance and power handling. This thing is more like a 9 inch woofer,luckily it just fits in the space I allowed for it. I have no doubt after seeing how this woofer is built that this box will be a real performer.
Last edited by Expertfabricator; 06-20-2009 at 02:20 AM.
Here is the same box in a more finished state. I keep finding flaws,very minor but the better I get this box the better the mold and future boxes will be right out of the mold.
Last edited by Expertfabricator; 06-20-2009 at 02:20 AM.
Couple shots of the Kicker L5 woofer,it measures 9 inches square outside dimensions. All cast aluminum basket,very nice heavy spring clip connections,dual voice coil,very well made. The wood mounting ring will be glassed right inside the box and become the mounting flange for the woofer. The woofer will be mounted with machine screws and "T" nuts.
Last edited by Expertfabricator; 12-09-2009 at 05:15 PM.
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New Shoebox sub design
