Making the Bass Booster, part one: the wood

The choice of wood comes first

Poplar is chosen for its ratio between lightness and stiffness. A blade must be set moving with little energy and return quickly to its position, and those two requirements rule out most denser species.

Drying

A piece that is insufficiently dry keeps moving after assembly. It distorts, its density changes and its behaviour drifts, which makes drying as decisive as machining for the stability of the finished product.

Cutting

It is at cutting that the orientation of the grain is decided. A blade whose grain runs along its length does not behave like one whose grain crosses it, and that decision cannot be put right at any later stage.

Thickness

It sets the stiffness and therefore the frequency range the blade reproduces best. A variation of a few tenths of a millimetre is audible, which imposes a tight tolerance at machining.

What is checked at this stage

Flatness, thickness and the absence of knots in the stressed areas. A defect spotted here costs one piece; the same defect found after assembly costs a complete unit.

What a natural material imposes

A rejection rate. No selection makes two boards identical, and accepting that rate is part of choosing a living material rather than a consistent industrial composite.

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