It is removable so don't hurt to try for yourself.
The best way I have found to get better bass is to compress the cushions and get your oils into the surface of the pad. The oils will seal with your skin easier and the denser cushion helps the bass keep some impact. You can experience this by spreading your fingers to the outer edge and slowly push down a quarter inch or so and the character of the headphone changes. To soften your surface and help compress the foam, hand wash them, rinse well and put under some weight to let them dry.