A resonance bump in a room's frequency response is called a room node. In the past, bass traps that were substantial enough to control nodes have been expensive and time-consuming to build. Auralex has solved that with the LENRD Bass Traps. LENRD stands for Low-End Node Reduction Device, and it is extremely effective at smoothing out low frequency room nodes, while still remaining affordable. It has an NRC of 1.50 for useful bass reduction.