Do you know how to control the volume of the computer while using unity?
The audio preferences has what I suppose could be considered a master volume, which I would -assume- can be controlled via a script (but don’t quote me on that, not tried it!).
Take a look here.
Also, here’s a tip that might be helpful. Here is a link to the Unity script reference. If you type something into the ‘search’ box in the upper-left, you’ll get a list of links related to whatever you typed in.
For example, if I type in ‘volume’, the second entry in the list I get back is:
AudioListener.volume
Controls the game sound volume.
In other words, the answer to your question, more or less 
The reason I mention this is that as great as the forums are, looking things up in the documentation is usually much, much faster. By using the documentation you can find answers to questions like this in seconds, whereas with the forums it might be minutes or hours, depending. So in short, the documentation is your friend
Funny : the fact that Audio Listener could have even ONE variable never crossed my mind. In the Inspector, there is nothing. So, to me, there was nothing to do too. Thanks you for the tip, lol.