What do you exactly mean "as they break in" is it some kind of running in you mean? Never heard of it before. Is it that the speaker cone get softer at the perimeter and will handle the bass notes better? I am just asking.
Mark Audio speakers need a time to loosen up the cone, surround and spider so they sound good, straight from the box all sound bad, some need 20h, but many need 100h or more of playing on soft volume before they are "broken in" and sound good. That braking in is something all speakers need, but for most it's hardly a few minutes, for a few like the Mark Audio speakers, it's days due to the special way the cone is made to be light and still have a high xmax and can do a wide bandwith. Mark Fenlon (the designer) stated that before on this forum (do a search) when he was still a member.
Surprising if you have hung around here. It is primarily the spider that breaks in, but the surround a s well. The cone itself can “settle” abit, but it is mostly a case of slowly turning the spider from a stiffened piece of “cloth” into something flrxible and compliant.
dave