Ohmic Audio

🔰 BEGINNER LEVEL: Materials and Basic Build

MDF vs Plywood vs Alternative Materials

MDF (Medium Density Fiberboard): The industry standard for subwoofer enclosures. Dense, consistent, easy to cut accurately, machines cleanly for circular cutouts, doesn't flex easily, takes adhesives and screws well. 3/4" thickness for all panels except front baffle (use 1" or doubled 3/4").

Why 3/4" MDF specifically: Provides adequate stiffness vs weight tradeoff. Thinner (1/2") flexes too much above 100W. Thicker (1") is heavier and harder to work with for marginal improvement.

Void-free birch plywood: Used in premium builds. Stiffer than MDF for the same thickness. Lighter. Shows natural wood edge nicely. More expensive. Harder to get perfectly flat for driver sealing.

Fiberboard alternatives (particle board): Cheaper than MDF, slightly less dense. Works adequately but absorbs moisture more readily. Acceptable for budget builds.

High-density polyethylene (HDPE) or fiberglass: Used in custom fabricated enclosures (vehicles with unusual shapes). More work to build but creates finished surfaces. Required for any vehicle where MDF won't fit the space.

Basic Assembly Procedure

Cutting:

Use a table saw or circular saw with a fine-tooth blade (80 tooth for MDF). Cut panels slightly oversized, then trim to final dimension. MDF dulls blades quickly — expect to replace the blade after 2–3 enclosures.

Marking and drilling driver cutout:

Use a circle jig (router with trammel bar) for clean cutouts. The driver's published mounting hole diameter is the cutout you need. Check the driver's template if provided.

Assembly sequence:

  1. Dry-fit all panels without adhesive first. Verify alignment.
  2. Apply PL Premium polyurethane construction adhesive to all mating surfaces.
  3. Clamp or screw together. Screws every 4–6 inches along joints.
  4. Pre-drill pilot holes to prevent splitting.
  5. Wipe excess adhesive inside. Let cure 24 hours.
  6. Apply second bead of silicone caulk inside all seams after adhesive cures — belt-and-suspenders sealing.
  7. Install terminal cup before installing driver.
  8. Install driver with weatherstripping foam tape gasket between driver and baffle.

Checking for air leaks:

With driver installed and terminal cup sealed, light a candle or incense stick near all seams while someone applies pressure to the cone from outside. Smoke movement reveals leaks. Seal with additional silicone.