The dry wall is hung on RC-1 resilient channel. there are two sheets that are only glued together with a high damping polyurethane glue. When the wall flexes, as it will at LFs, the glue is put into shear and damps the flexing. At HFs the wall is basically rigid because it is too heavy to move at HFs.
Membrane absorbers are fine if done right. Its all good and effective if the design is done right for the problem at hand. The biggest problem that I see is people using smallish absorbers, which even if they do have some LF absorption are too small to offer much damping to a large LF mode. It takes a panel the size of a wall to do much of anything at 50 Hz or so.