Midi control of volume in midi tracks

new to Cubase, Using Cubase elements 7, windows 10, using the included halion VST synth. I Have a project to do. That project requires me to control the volume of midi tracks with midi input.
In more detail, We are building a music display with a bunch of overhead sensors. Each sensor “watches” a particular area of the space with graphics describing a particular instrument. The full musical piece [14 parts] loops at a low volume. when a visitor is detected by a sensor, the track related to the graphic needs to come up to full volume and drop back when they leave. When I googled this issue , other forums say in so many words… you can’t do that. Now I am using a home-brewed midi controller for this so I can generate ANY midi message[s] I need in order to do this. The question is how do I get cubase to do it’s part?
What I have done so far is send midi CC messages #11 expression, at 1 sec intervals, 0 expression then 127 expression as a test. I can make this control the volume of whatever track I have selected regardless of the midi address sent or the midi address of the track. Also i have found the faders in the mixer window have no effect on individual track volumes just a red fader on the right controls the volume of everything. I do see the VU meters in the mixer going but the sliders…no effect.

Hiya Zilch99
I’ll try to help a bit.
Firstly CC11 is expression as you say, but CC7 is volume. some synths and some patches will vary with CC11. It may not change the volume, but it may change the timbre or “mood” of the sound.
Next, are you taking about the midi faders on the mixer, because they are displaying velocity by default.
Not sure how you would do the task you’ve set out to do, but this link may be of help.

Have a wade through it and the tips I’m thinking of are start at the top of page 2.
Hope it helps

I wouldn’t mix with midi, it’s not usually a linear curve.
You can move a midi slider quite a bit with no effect then you get a lot of change right at the last.

Depends on your synth.

I use separate audio channels for each midi channel on the sonic 2, not sure if you can do that with the included version.

If your hardware can put out the midi I would think it could be done.

Yea, using the right CC would be a good start.

I think you could convert midi to control the audio sliders if you wanted to learn the Generic Remote.

Lot of R and D.