The only effect David left out, because it's more subtle, is the stuffing acting as a very very minor bass absorber. Overall, they are not most effective as resonators, however. The diffusion/diffraction effects are their strongest, per Jon Risch.
Even with only 2 of them in my room I get significant effect from proper placement (varies with room and setup) and moving them around demos how they change the reflection picture in the room space. Sometimes for non-audiophiles who ask I do that demonstration and they're amazed. In fact, when I first built mine, my sound engineer son walked by and commented that they "focused" the sound to his hearing, which is pretty much the impression they give when working and probably why Argent named them "lenses".
As to the original question, I believe that David answered that spot on for the inmate.