I made a skyline style sound diffuser / wall art : r/DIY
How To Make A Gorgeous DIY Skyline Diffuser
BUBOS 36 Pack Acoustic Diffuser,DIY Acoustic Panels Sound diffuser Panels Full frequency sound absorption(4 x 4Inch),better Acoustic Treatment for Recording Studio, Office, Home Studio – buybubos.com
How to Make a DIY Sound Diffuser (step by step) - Soundproof Expert
How Easy is a DIY Sound Diffuser to Build? – Acoustic Fields