In modern studios acoustic diffusers are used to control wall reflections and create a smoothed sound environment. QRDs are designed for one frequency which might be suspicious for some users. Therefore I though about a design which uses 2 frequencies. It's shape - in detail the angle of the elements - morphs in between two possible positions:

QRD - Princip

Acoustic diffuser with two different element angles which change according to frequency definition


QRD - Architecture

The ready built diffuser design:

Quadratic residue diffusers using 2 orientations to build a wall.

Several Diffusors joined to get a complete wall

You are encouraged to use the designs for private use.

 See the former article about QRDs