Auralex Studiofoam Wedges (6 Pack) …

Auralex Studiofoam Wedges (6 Pack)  ...Auralex – Auralex Studiofoam Wedges (6 Pack) Burgundy
Recommended for medium to large areas like concert halls, gymnasiums & churches, those rooms with pronounced low frequency problems and for those rooms where sonic accuracy is mandatory & maximum absorption is required. 4 inch Studiofoam provides excellent low frequency control (3X that of 2 inch Studiofoam) and can make rooms very dry. In some instances, using 4 inch on your walls can negate the need for significant bass trapping.
Auralex, Acoustic Treatments 4SF24BUR