It isn’t as binary as that though. There are semi-open back headphones. Also pad material and shape as well as clamp affect the front seal and therefore how closed the front volume is. IE - using a pad that doesn’t seal as well is similar to venting the front.
I’m realizing that even the on-ears like Grados will have some level of front seal. The Prestige series front seal will be less than the Reference series due to the small, thin pad design. Maybe that means swapping to a circumaural pad on a Reference is not as radical of a change as I originally thought.
This might also explain why the Geekria pads that I liked increased bass response. Adding a hole in the middle of the pad might allow it to seal a bit better. If so, then the only meaningful difference in the higher end Prestige could be the pad. A stretch I know, but interesting to think about.
I wish there was a reliable source of FR measurements for the Beautiful Audio pads vs stock. That would be some assurance for me. But I don’t own a Reference anyway - yet.
I don’t think it’s just your messed up ears. Perception of soundstage, especially depth, is more complex and individual than perception of tonality - which is already complex and individual.
I came very close to ordering a pair of F pads from their site, but I realized what I really want to do is have a pair of 325x to compare with my 125x with F pads.
The F pad is the same as the old TTVJ flat pad, which is itself a throwback to the pads that came on the old Joe Grado HP line of headphones, so people have been using flats on Grados for a long time, but Grado themselves just started doing it again officially. Other than the wireless one and the IEMs, all Grado pads will fit all Grado headphones (not to say they necessarily sound good, though).
Updating 4 years later. Someone recommended changing pads and they were right! It was the F Pads that saved the Grado line for me. Grado SR80x, SR225x, SR325x, all with F Pads and could not be happier. Like I said 4 years ago, I am not a basshead, but changing the pads not only revealed the capabilities of the Grado cans, also got rid of the shrillness that bothered me so much.
So no need to go above the 325x. Just made sure everything I got from Grado had the F Pads.