Building a speaker box for a 6x8 speaker out of mdf
The video demonstrates building a custom MDF speaker box sized for a 6x8 speaker, covering design, cutting, assembly, port and terminal installation, internal damping, and finishing. It walks through the full DIY process so viewers can construct a sealed or ported enclosure using basic woodworking tools and materials.
Build Sequence
1. Design and calculate internal volume
Decide whether the box will be sealed or ported, measure the speaker depth and cutout size, and calculate internal volume and (if ported) port dimensions. Sketch panel layout to minimize waste on MDF.
2. Lay out and mark MDF panels
Mark all panel dimensions, speaker cutout location, terminal cup location, and port location on the MDF sheet using a tape measure and square.
3. Cut panels and cutouts
Use a circular saw or table saw to cut the main panels. Use a router, hole saw, or jigsaw to cut the speaker flange hole, terminal hole, and port tube opening to size.
4. Dry-fit panels
Assemble the cut panels without glue, ensuring edges align and the speaker and terminal cutouts line up. Adjust as necessary for fit.
5. Glue and clamp assembly
Apply wood glue to joining edges, assemble the box, and clamp squarely. Reinforce joints with screws if desired (pre-drill pilot holes to avoid splitting).
6. Seal internal seams and install terminal/port
After clamps are removed, apply silicone sealant to all internal seams for an airtight seal. Install the terminal cup and port tube, sealing around them with silicone.
7. Add damping material and wire speaker
Place polyfill or other damping inside the enclosure (amount per design), run speaker wire to the terminal cup, strip and attach leads ensuring correct polarity.
8. Mount speaker and finish exterior
Screw the speaker into the front baffle, test for air leaks, then sand edges, prime, and paint or veneer the box. Install grill if desired.
Frequently Asked Questions
How do I ensure the box is airtight?
Dry-fit panels first, then glue joints and use silicone sealant inside all seams and around terminal cups or ports. Test for leaks by pressing slightly near seams and listening or using soapy water on joints.
VIEW FULL ARTICLE →How much polyfill should I use?
Start with a light stuffing that lines the walls and fills about 10–30% of the internal volume depending on desired damping; overstuffing can overly damp low frequencies. For small boxes, a thin layer is usually sufficient.
VIEW FULL ARTICLE →Related Builds
Parts Used (10)
Main material for panels; amount depends on box size (often one 4x8 sheet sufficient for a small box).
Driver shown/used by builder; price varies widely depending on model. Assumes a mid-range replacement speaker.
Used to connect speaker wires externally; cut a hole in MDF and fasten with screws.
Used to seal internal seams and speaker/terminal joints to make the enclosure airtight.
Only required if building a ported box; diameter/length chosen per box tuning calculation.
Placed inside the box to reduce standing waves and alter effective volume.