Bowl and flat pads' dual foam density (the stiffer layer on the rear is the main culprit) entraps low frequencies as their only way to conduct warmth from the driver to the ear, muddy warmth that is.
If you seek clarity on a Grado headphone you need to use “uniform” foam pads like comfies or better, HD414's.
For HD414's to have bass I did
this to them, which I'm calling the sunflower mod because it's bright yellow, has petals and is hefty (sounding).
I'm big on Scotch tape mods. This one provides at least twice the bass conductivity of the original
Grado bass head mod, but with the added clarity and comfort benefits of the HD414 pad.