Uhhh... I'm going to assume those "big round cushion things" he's talking about are tube traps. They have to be that large, you know because physics. Bass wavelengths are VERY long, and they need a lot more mass to react to. I'm not an acoustics expert, so its possible that the Holograph may have some type of diffusion effect. So can almost anything. A bookshelf lined with different sized books can act as a diffusor. Even a house plant can. None of those are effective at sub 100Hz frequencies though, and neither are these Shakti things.
