In the case of ATC (which I import to the US), there is no driver compensation, just filtering. One would completely remove the driver connection to the [passive] crossover and install a new connection straight to an amplifier, with an active crossover determining level, slope and frequency. This is not an easy thing to know and is usually beyond most of us to "self calibrate" the speaker without measurement equipment and a lot of the technical data on what the final curve should look like.
I can recalibrate ATC’s in my shop when drivers are replaced or upgraded, but I have a $12K measurement system with an Audio Precision device (a computer basically designed for measurement) and special acoustical software and a "calibrated to the computer" mic for the measurements. I know no one could do that at home, even if they had the gear, because knowing what the original curve was or should be is critical to avoid changing the way the speaker sounds dramatically. Experimenting, one could easily ruin the sound of a system and not know how to get it back without sending it back to the factory.
Brad