Auralex 4" StudioFoam Wedge - 2x4 Foot Absorption Panel (Purple / Box of 6)4" Studiofoam Wedges are recommended for rooms with pronounced low frequency problems or where sonic accuracy is mandatory and maximum acoustic absorption is required (e. g. voiceover or drum booths, forensic audio labs and mastering rooms). 4" Studiofoam Wedges provide 3 times the low end control of 2", and can effectively tame even the worst sonic anomalies. In some instances, using 4" acoustical Studiofoam can lessen the need for significant,