There's of course some information on our site, might have been missed. Short version - it is about the signal chain down to the interaction between the gear at a new level, the gain staging of the whole chain, and how things are tweaked by the award-winning engineers at Lurssen Mastering - especially Gavin Lurssen himself. You also have the ability to make tweaks as this is not just a one-trick/one-knob pick-a-preset and go type of product or experience. OK that was not so short of a version. Here's the site info, though, slightly longer:
From
http://www.ikmultimedia.com/lurssen
Lurssen Mastering Console is a totally new approach to digital audio mastering.
It provides a complete emulation of the entire mastering processing chain used by world-renowned mastering engineers Gavin Lurssen and Reuben Cohen and their team.
This chain includes tube equalizers, solid state equalizers, limiters, de-essers and solid state compressors.
The simulation of this chain reflects their “whole chain philosophy” — a belief that outstanding audio mastering comes from the careful selection and routing of gear, and the subsequent interactions created by those choices.
Lurssen Mastering Console models and recreates the interactions between the individual processors in its chain down to the actual gear hookup schematics themselves.
This approach effectively gives you access to over 25 years worth of knowledge in the form of workflow secrets, special techniques, signal chains and technical knowhow.