IG Acoustics – 2D QRD Diffuser

2D QRD Diffuser

This acoustic diffuser panel is based on a two-dimensional QRD design (Quadratic Residue Diffuser) and was developed to scatter sound energy evenly in two spatial directions. Unlike absorbers, which reduce sound energy, a diffuser distributes reflections in a controlled way throughout the room while preserving the natural liveliness of the sound image.

The panel consists of a 7 × 7 matrix with a total of 49 diffusion chambers, whose depths were calculated according to the mathematical quadratic residue sequence of order 7. This structure reflects sound diffusely both horizontally and vertically, breaking up directional reflections and creating a more homogeneous sound field.

The calculation is optimized for a design frequency of 1475 Hz. With a maximum construction depth of 100 mm, the diffuser is particularly effective in the mid-frequency range, which is crucial for speech intelligibility, spaciousness and detail reproduction. The period width of the panel is greater than the design wavelength, resulting in even and efficient sound scattering.

The construction is based on a precise cross structure made of fins, forming a matrix of 49 individual diffusion chambers. Blocks of different heights are inserted into this structure to create the precisely calculated depths. The gradation is made in 16.7 mm steps and ranges from 0 to 100 mm.

Technical data

Diffuser type: 2D QRD (Quadratic Residue Diffuser)
Order: 7
Matrix: 7 × 7 diffusion chambers (49 pcs.)
Design frequency: 1475 Hz
Maximum construction depth: 100 mm

Variants:

• 50x50x11.5 cm – approx. 5 kg
• 100x50x11.5 cm – approx. 8 kg

Typical applications

Recording studios and control rooms
Home cinemas and hi-fi listening rooms
Rehearsal rooms and music rooms
Concert and event spaces

By scattering reflections in a controlled way, the diffuser improves spaciousness, transparency and localization in the sound image without overdamping the room acoustically.