07 · Bass traps

Membrane Column

The floor bass trap standing up and stacked, tuned to one room mode you pick.

size: 300–750 wide, up to 2800 mm tall
tuning: depth and mass sheet found for the mode
range: about 35–90 Hz (calculated)
package: cut list, hardware, print files for your printer

Overview

How it works

A tuned trap for one room mode, built from the floor bass trap's box standing up: a membrane on an elastic gasket over a sealed box of air, modules stacked floor to ceiling.

The membrane is a mass on the spring of the air behind it (and of the gasket): at its resonance it moves and the wool behind it turns the energy into heat. It works over a wider band than the slot column and forgives small errors in the build.

f₀ ≈ 60 / √( m · d ) m = membrane kg/m², d = air depth in m, before the gasket and the bending of the membrane

Where

Like the slot column: where the chosen mode presses hardest, the rear wall between the diffusers for the length modes.

Tuned for you

The configurator finds the shallowest box that lands on your mode, within the depth you allow, and adds a mass sheet on the membrane only if it has to.

One module in section, the wall on the left. The depth sets the frequency.

Figures

Sizes and numbers

Mode	Depth	Mass sheet	Works	Column
40 Hz	420 mm	6 kg/m²	34–47 Hz	≈ 62 kg
50 Hz	445 mm	2 kg/m²	43–59 Hz	≈ 64 kg
60 Hz	450 mm	none	51–70 Hz	≈ 65 kg
80 Hz	195 mm	none	68–94 Hz	≈ 40 kg

Calculated, not measured

450 mm wide, 2400 mm in 4 modules, MDF 6 mm on EPDM, 50 mm of wool, deepest box allowed 450 mm. Calculated, not yet measured: measure one module in your room before building the rest.

Safety

Screw it to the wall before you let go of it. Safety information →

Build

Details

01300–750 mm wide, up to 2800 tall in 350–900 mm modules; the membranes, gaskets and wool of the floor bass trap; the same printed brackets and jigs.
02Every module screwed to the wall and to the module below from inside, before its membrane goes on. Two printed brackets on top.