With a passive crossover design the crossover point can be defined in different ways, such as acoustical or electrical. The slopes can also be asymmetrical so in some cases a "2K" point may be electrically higher (say 2.2-2.5K) for the tweeter.The ribbons and planars do exhibit audible distortion if pushed too low or the low end response isn't properly shaped. Slopes that are too shallow can also create problems.