Universal Audio UAD POWERED PLUG-INS ver.6.1 - Manual (Page 325)

UAD Powered Plug-Ins Manual - 325 - Chapter 30: Manley Massive Passive EQ
As Bandwidth is increased in Shelf mode, a bell curve begins to be intro-
duced in the opposite direction (i.e., overshoot). For example, if the Shelf is
boosted, a dip is created at higher Bandwidth values. At maximum Band-
width, this overshoot curve is pronounced. The effect of the Bandwidth control
in Shelf mode is shown in
Figure 108 below.
Figure 107. Effect of Bandwidth control on response curve in Bell mode
Figure 108. Effect of Bandwidth control on response curve in Shelf mode