Indeed. One of the fundamental tenets of this thread is that vintage ortho 'phones can often (not always, but often) provide almost any kind of sound, including bass sound-- call it your personal bassstyle-- from frighteningly tight to mellow and all the way to downright floomfy, depending on the owner's willingness to spend time and effort and which headphone he/she starts with. I personally tend to push perceived-flat response and tight bass (because I'm a waveform-fidelity kinda guy), but that's not the only option.
SFI: Don't forget, this is one of those off-label "it's not supposed to work" things. The SFI was originally meant to be a tweeter, one of an array, in a gigantic panel-shaped multiway dipole speaker built by Sawafuji back in the '70s. And nearly all the SFI drivers you'll find for sale today really are tweeters and nothing more-- ours is the dipole version, which gives it a special dispensation. Regardless of its hidden talents, since it was meant as a tweeter, it's spec'd that way. But just as Sennheiser's reputed to have used a microphone capsule to create the HD 414 headphone, sometimes off-label works just fine.