Edwyn Acoustics Bass Trap 1.2m tall ( Stackable ) available in Black or Beige – Absorption and Diffusion. Recommended to be placed in the corners of the room $599 - Simply Hifi
Making Corner Bass Traps - Hzandbits.com
DIY Acoustic Panel and Bass Trap Frames -
DIY Bass Traps: You NEED These in Your Studio - Produce Like A Pro