Trae
500+ Head-Fier
Modify/change the earpads and bend the headband. Audio Technica's 53mm drivers have the potential to be bass monsters, but either the clamping force, the earpads, or both, prohibit them from bringing it out. If the a900x's headband has a light clamping force like my AD900 did, you can try bending it to get a better seal around your ears. The earpads look okay on those headphones, but you may want to stuff some cotton balls underneath it to let them seal around your ears better and create more distance between your ears and the driver grill. Plus, the cotton lets you bend the headband less in order to get the proper seal because they'll be thicker.