A resonance bump in a room's frequency response is called a room node. Bass traps substantial enough to control nodes have always been expensive to buy or intricate and time-consuming to build - not anymore.
The MegaLENRD Bass Trap (Low-End Node Reduction Device) is extremely effective at smoothing out low frequency room nodes and is just a bigger version of the original best-selling bass trap. At twice the width (extending 24" along each wall, not 12" like the standard LENRD,) the bass trap is substantial enough to handle low-frequency problems in rooms of any size and is the only broadband absorber effective below 50Hz.
Outstanding broadband absorption, especially at low frequencies
Effective to below 50Hz
Fits room corners and wall/ceiling junctures perfectly