batsbrew
yea, load dump is different than the mass lite..
mass lite uses a speaker motor as an active load component...
moving air is the best.
when you can't move air, either DI to a IR loaded with speaker impulses,
or what i do, a specialized DI with a cabinet filter built in, ala palmer, Radial, etc.
I have a Weber Mass, but the box (not the output), rattles and buzzes and I switched to the Load Dump. The Mass that I have has a driver in it, but not the speaker cone so it doesn't seem to be moving air - if it did it wouldn't be silent. It's not an issue for me I have various Marshall and tweed clones set up in my studio getting sounds that I like, but these days I normally use S-Gear.