Hmmm...maybe I have something else misconfigured then. Right now the main volume in the volume window controls what I hear on my computer (server)...not the actual output that people hear when they tune in. I have CUE output disabled.
I suggest you lower the Main Volume in the Volume window and manage the Studio volume via the Cue Output.
(That requires to configure the CUE output in Audio Mixer Pipeline and enable the cue button on all your players, if you only have one soundcard, you gotta set the main output to silent output)