Understanding Sound Diffusers

Unlike absorbers, which reduce reflections by turning sound energy into heat, diffusers scatter sound waves in many directions. This preserves energy in the room while breaking up strong reflections that cause harshness, echo, and phase issues.

How Diffusers Work

When sound waves hit a flat, hard surface, they reflect in a predictable direction, often causing flutter echo, harshness, and frequency buildup.

Diffusers solve this by using irregular surfaces (like wells, curves, or angled blocks) to scatter sound across time and space. Instead of reflecting in one direction, sound is spread out in a diffuse field, reducing the perception of echo while preserving spaciousness and energy.

There is no significant loss of sound level, only redirection and redistribution.

Why Diffusion Is Important

Well-treated rooms can become too dead if only absorption is used, especially for music listening or critical mixing. Diffusion helps by:

1. Preserving Liveliness
It reduces harsh reflections without eliminating the reflected sound entirely, keeping the room sounding open and engaging.

2. Enhancing Soundstage and Imaging
By disrupting direct reflections at the listening position, diffusion improves the ability to localize instruments or voices in space.

Types of Diffusers

• QRD (Quadratic Residue Diffuser): One of the most common types; uses wells of varying depth.
• Skyline or 2D Diffuser: Scatters sound both horizontally and vertically.
• Poly or Barrel Diffuser: Uses curved surfaces to spread sound in a wide arc.

Each has different diffusion patterns and frequency ranges depending on depth and surface geometry.

Implementation

Many rooms benefit from the proper placement and planning of acoustic diffusers. Use tools like Room EQ Wizard (REW) to identify what your specific room needs, or consult with a local acoustician for tailored advice.