Yes they are adjustable. There is a threaded stud that goes through the aluminum and both cones screw on to. With the right sized fender washer you could probably get 1/4" to 3/8" and not have a noticable gap between the bottom cone and aluminum strut.
Means you could also make them taller with...
Bought these feet off eBay, have been looking for a way to stabilize the ESL's (have small kids).
Listing was called "4pcs Combined Type Audio Speaker Shockproof Spike Foot for Subwoofer Bookshelves"
Tried to come up with a way that didn't require modifying the speaker enclosure, so I can...
Was wondering if all the ones that have the DC power supply barrel can use the same power supply. Not the IEC models. Like in the picture below. This would work with the ones that come with the ESL X's and visa versa?