Finishing Speaker Cabinets

Finishing speaker cabinets for sound system work is about survival: the coating has to take knocks and damp, and the hardware has to carry a heavy plywood box with an 18" driver inside (the WM1850/8 alone is 20 kg) through years of loading. Textured polyurethane, a steel grille, corners, recessed handles and a plan for moving it.

Preparation

• Fill screw heads, voids in ply edges and gaps; sand flush.
• Round over edges slightly. Sharp arrises chip and coatings don't grip them well.
• Remove all dust before coating.
• Take the driver out, or mask it, before painting.

Wear a dust mask when sanding and follow the coating maker's ventilation advice.

Finishes compared

Textured polyurethane

Coatings made for speaker cabinets give the hard, slightly rough black finish seen on professional PA boxes. They resist scuffs, hide minor surface flaws and touch up cleanly. Follow the product's instructions on primer, coat count and drying time. Water-based and solvent-based versions have different ventilation and safety requirements.

Paint, tolex and carpet

Exterior or floor paint is the budget route: prime, then several thin coats. It protects the wood but wears faster. Tolex wipes clean and looks sharp on smaller cabs, but tears on edges in transport. Carpet is cheap and soaks up knocks, but holds water, which makes it a poor choice for outdoor work.

Grilles

Perforated steel protects the cone from fists, cases and cables.

• Stiff enough not to flex, with enough open area that it doesn't whistle at high level.
• Mounted so it cannot rattle; rubber edging or foam strip helps.
• Clear of the cone at full excursion. On a long-throw 18", allow for Xmax plus overshoot. See Xmax and excursion.
• On scoops and horns, cover the mouth if the design allows, not just the driver.
• Acoustic foam or cloth behind it hides the driver and keeps dust out.

Corners

Metal or tough plastic corners take the hits that would split ply or chip the coating. Stacking corners locate into the cab above and help a stack sit square. They do not replace straps or safe stacking practice.

Handles

Recessed handle cups sit flush, so they don't snag when stacking or loading. Fit them where the weight balances, usually on the sides near the top, so two people can lift together. Bolt through with T-nuts or nuts and washers, not wood screws, and seal behind them: an air leak in a reflex or horn cab is a noise source and a tuning error.

Castors and dollies

Bolt castors to a strong mounting board on the back or bottom, never screws into ply. Many crews prefer separate castor boards or dollies so the cab sits flat on the floor when playing. Either way, the cab must be stable when stacked. See loading and stacking safely.

Final checks

Refit the driver, check every fixing, then run the checks in testing a new cabinet. New hardware is a common source of buzzes, so sweep slowly and listen for grilles and handles. Building from scratch? See the scoop bin build guide.

Sources: WM1850/8 weight from the Wavemark spec sheet. Coating, safety and drying guidance varies by product: follow the manufacturer's data sheet.