Making the Bass Booster, part two: the finish

Sanding is not a finish

Going to grain three thousand leaves a closed, even surface. It is not an aesthetic requirement: an open surface absorbs moisture unevenly, and a piece that absorbs unevenly distorts.

Sealing

It fixes the state obtained. Once the surface is sealed, the blade stops exchanging freely with the surrounding air, and its behaviour becomes predictable and repeatable from one unit to the next.

Assembly

That is where the coupling between the exciter and the blade is decided. The tightening is checked rather than estimated, because too high a torque restricts the vibration and too low a torque leaves play.

Testing

Every unit is listened to before being closed. A voice reveals a parasitic resonance or an imperfect contact within seconds, where a measurement would call for a bench and more time.

What can still be rejected at this stage

A unit that does not respond correctly despite a validated blade. The fault then comes from the assembly, it can be corrected, and the final check exists precisely to separate those two cases.

What this method implies

Time and sorting. It is the price of a product whose heart is a piece of wood, and it is also why it is not made at the pace of a fully automated production.

The principle is developed on the Magic Speaker page, and ceiling sound on the dedicated page.