Dedicated 2 channel mid-sized listening room converted from a spare bedroom. 90% of the acoustic treatment is made with cedar and pine as fun DIY projects built over the past 5 years.

Front, rear and one of the side walls have DIY sound diffusers based on Tim Perry's (Arqen) fractal designs (http://arqen.com/sound-diffusers/).

Ceiling above listening position treated with DIY two-dimensional QRD diffuser.

Ceiling in the front of the room is angled to minimize parallel surface areas and front side walls covered with standard 48x24x2 absorbing panels to eliminate flutter echo.

Floor is covered with regular carpet, but I use wool rug in the listening position to minimize 1st reflections coming from the floor.