Today I made my first Quadratic Sound Diffuser. : r/WeAreTheMusicMakers
Quadratic Formula Sound Diffuser Studio Wall Art Black and Blue - Etsy UK
Arrowzoom New Quadratic Skyline Acoustic Wooden Diffuser Soundproofing your Home & Studio for Music or Sound recording Noise Cancellation 23.6" x 23.6" x 3.9" inches or 60 x 60 x 10cm SD1204 :