on these MA Audio subs i'm looking at, the specs say they have "24mm peak to peak XMax"... does this mean that they have 11mm XMax one way? or 24mm Xmax one way?
I'd be a bit wary, some people overrate the Xmax specification and tend to confuse people. Make sure they're not referring to mechanical excursion, as you'll never use it nor will you want to.