So now that I have my Spring1 back from loomisjohnson (he had a great succinct review at the blog) I decided to remove the entire mesh screen grill for a quick test. While I don't feel it really changed the issue with the bass, it is still pretty woolly because the boost begins rather early into the lower mids-actually it decreases the sub-bass a little, it does increase the upper midrange peak and treble quite a bit to give the impression of less bass. What is interesting is how drastic the tube coupler resonance all of sudden shows up, I don't really hear this peak. I think it is fine with the mesh because the boost is just right. They do have a filter over the BA, it would be nice if there was a source of those somewhere on ALI. Micropore tape on the nozzle could be an option, but harder to work with. Anyway, here is measurement.
Also, after listening to the SImgot EN700pro and 700bass which has a fantastic bass profile that I love, the Spring1 bass issues are very apparent when listening to Tool Forty six and 2 for example. It's not a deal breaker, I just find that for rock type music I prefer the bass of the Simgot.