Interesting filter behavior in Cubase Pro 8

Here’s 2 screen caps of the same VST instrument playing through the channel.

filter Hz:
HC is at 18306Hz
LC is at 126Hz

In the 1st image the HPF and LPF in the PRE section are NOT engaged.
** peak shown on fader is -3db


In the 2nd the HPF and LPF in the PRE section ARE engaged.
** peak shown on fader is -1.8db

To better illustrate here’s the same test with CurveEQ loaded post fader
and the curve set to average and
the capture was taken AFTER the settle to stable unchanging average was reached.

In the 1st image the HPF and LPF in the PRE section are NOT engaged.
** peak shown on fader is -3db

In the 2nd the HPF and LPF in the PRE section ARE engaged.
** peak shown on fader is -1.8db