Material Thickness & Resonance: Building a Dead Cabinet

The goal of a speaker cabinet is simple: let the speaker driver make the sound, while the cabinet itself remains completely silent. This is often referred to as building an acoustically "dead" cabinet.

Why Thickness Matters

When a speaker cone moves outward, it pushes air into the room. When it moves inward, it compresses air inside the cabinet. This internal pressure pushes against the walls of your enclosure. If your walls are too thin or flexible, they will vibrate.

Panel vibration causes two major problems:

• Loss of Energy: Energy that should be producing bass is instead wasted on flexing the wood, resulting in "muddy" or weak low-end response.
• Unwanted Resonance: Flexing panels act like their own speakers, emitting sound at their own resonant frequencies and coloring the overall sound of your music.

Choosing the Right Material

For most home audio, studio monitors, and subwoofers, 18mm (3/4") MDF (Medium Density Fiberboard) or Baltic Birch plywood is the gold standard.

• MDF: Dense, heavy, and acoustically dead. Perfect for stopping resonance.
• Plywood: Lighter and more structurally rigid, making it the preferred choice for touring PA speakers or guitar cabs that will be moved around frequently.

When to go thicker?

For high-excursion subwoofers (e.g., car audio subs pushing 1000W+), the internal pressures are massive. In these cases, builders often double up the front panel (the baffle) to 36mm (1.5") to ensure the heavy driver is rigidly mounted and vibrations are minimized.

In Volume App, you can account for this by setting the overall cabinet thickness to 18mm, and using the Thickness Overrides feature to set the Front Baffle to 36mm!