Recording Sound Levels. 1 M/E, Decklink, Media Express

I have an ATEM 1 M/E connected to a Decklink Mini in a Win7 box. I am using Media Express to capture. So far, the only way I have been able to control the sound recording level is to play with the output volumes from the 1 M/E.
There should be a way to control it at the Win7 box, but it eludes me.
What am I missing?
TonyT

Generally you cannot adjust the master level of an audio output that is digital (ie HDMI) You can adjust the level of software running into it (ie the volume of media player). If your software odes not have volume then the level should come in and out the same. Create a few files with audio tone at 0, -10 and -20 db and then play them from the source machine and check the input level. If you are connecting digitally. If everything is working well you should be able to get the same level you are playing end up on your recordings while all your faders are at unity.

If your material is well prepared you should have no problems.

One of the issues is that we have to run both the input and output way up on the 1 M/E audio control panel to get a decent volume on Media Express. This also affects the audio level out the XLR connections and makes it way too high. I am getting ready to connect some "remote" monitors in some of our classrooms via HD-SDI using the 1 M/E aux outlets and I am worried that their volume will also be too high.
It really seems like the volume should be adjustable is either in the decklink mini or Media Express. Is there some setting I am missing?
TonyT