This graph shows the bandwidth from 10Hz to 100kHz and what happens with +16 db of boost at 200Hz. When you push the Shelf button, you can see that the 200Hz center frequency not comes down about 3db’s and the Shelf rises all the way to 10Hz.
10Hz to 40kHz
Here, we see a graph for both boost and cut of 200Hz but this time the bandwidth is 10Hz to 40kHz. The reciprocal boost and cut both show the comparisons of Bell and Shelf modes. This applies similarly for the high frequencies as well.