How to Build Non-Ported MTX Speaker Boxes

A non-ported speaker box is more commonly known as a sealed box. MTX is a specific brand of loudspeaker, made primarily for cars. Sealed boxes for loudspeakers are the predominant speaker type manufactured. Therefore, a non-ported MTX speaker box is a conventional air suspension speaker design using MTX loudspeaker components in a sealed box design. You can build a box from scratch using birch plywood like manufactured speaker cabinets, or you can choose to use medium density fiberboard (MDF), a preferred speaker building material of audiophile designers. Ready-made speaker cabinets can also be purchased.

MTX loudspeaker driver
Speaker building software
Thiele/Small parameters
1-inch plywood
Table saw
Power drill
Glue
Wood screws
Clamps
Sand paper
Wood puddy
Speaker wire
Connection terminal
Silicone caulk
Non-drying caulk
Router or circular saw attachment

Instructions

- 1
  Pick the MTX loudspeaker(s) that will be housed in the sealed cabinet. Popular sizes are 10 inches to 15 inches for most car and home theater designs. Then download winISD, a free speaker design software that is widely recommended. (See Resources.)
- 2
  Use the Thiele/Small (T/S) parameters. These are supplied with every MTX loudspeaker. They are critical to enclosure size. They are also available online (see Resources). Plug the T/S parameters into the software building program.
- 3
  Determine the box dimensions. Speaker building software will do this for you.
- 4
  Get the enclosure wood product. Birch plywood or MDF come in sheets. Cut box pieces to size with a table saw, or have the home products store where you buy the wood make the cuts for a small fee.
- 5
  Glue the sides to the top and bottom (or end) pieces. Drive wood screws through the sides into the inset pieces to further secure the connections. Clamp the enclosure with furniture clamps, and let it dry for eight hours. (Clamps can be removed after one hour.)
- 6
  Make the back panel cutout. If building a powered sub, the cut-out accommodates the plate amplifier. Otherwise, the terminal cup space is cut out in the back panel. Glue, screw and clamp the back panel to the box after making the cutout.
- 7
  Make the cutout for the front panel loudspeaker. Use a hole saw or router. Before attaching the panel, caulk all inside seams of the box with silicone caulk. Allow 15 hours for the caulk to dry. Silicone caulk emits gases that erode speaker surrounds (the flexible portion beyond the cone of the loudspeaker).
- 8
  Glue, screw and clamp the front panel. From the opening in the front panel (for the loudspeaker) and rear panel (for the terminal cup or amp), use silicone caulk to caulk the interior seams of the front panel. Let dry for 15 hours.
- 9
  Sand the cabinet. Use wood putty to fill countersunk screw holes. Sand again. Router the box edges for rounded corners. The cabinet is ready for the installation of the hardware.
- 10
  Install the back terminal cup. Affix the terminal cup with glue. Caulk around the interior perimeter of the terminal cup or plate amplifier. Allow sufficient time for the caulk to completely dry.
- 11
  Attach 12-gauge speaker wire between the terminal cup and the MTX loudspeaker/driver. Then attach the MTX speaker. Use wood screws and a non-drying caulk around the speaker frame to ensure an airtight seal.
- 12
  Finish the cabinet if desired with your choice of wood veneer, paint or stain.

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