On the screws. If the screws are on too tight, they will deform the rubber and result in poor seal or other strange behaviors. I backed the screws off to ensure the rubber surface was uniform. It wasn't the protrusions causing the issues for me. It also wasn't an "open" vs "closed" headphone issue but rather an issue of where the pads happen to lie. Seal issues occurred when the pads happened to lay on an area which isn't uniform. A good seal would still be obtained if the pads were complaint enough or happened to be placed in a way that avoided the non-uniform areas. A lossy chamber headphone will still exhibit some sort of bass rolloff, albeit less than stronger sealed chamber headphones. The HEQ compensations showed up as too lean and too bright IMO. For example, I didn't think the Denon D9200 had -5db bass shelf and +5db bass shelf. Nor I do think the Clear have that kind of lean bass per the HEQ comps.