Halion voume problem

In a project where I had assign bass to Halion, fingered bass, I couldn’t hear it in the mix. It’s velocity is up with some maximum and the channel volume is up all the way, but it is buried so that I had to start turning down the audio from the midi synths way below the recommended ~3/4 on the mixer, down to about 1/4. One problem is that the synths all have their own audio channels on the Presonus SL16R mixer, because their audio outputs are plugged into those channels, while the Halion, as well as audio tracks, have no such individual channels and only setting the master fader affects them. So I put this up to the 3/4 level to hear the bass and then have to turn everything else way down. Is this normal. Can’t Halion be more equal to other tracks? Ideally everything’s faders should be about 3/4 from the top, I think.
Also, midi tracks assigned to the Akai Z8 sampler are not affected by volume levels in cubase. I have to go to the device and bring its volume way down in its mixer from the default 0 to about -17 or more to avoid drowning everything out. Could this have been set up when I initially added it as a midi device?

Weird. When I actually recorded the Halion bass audio onto an audio track, it was much louder that the other synths ad had to be turned down.