Lower volume level below 1

The way to do this, is to have your main volume set to 100, and set your Chrome (or whatever program) to 1. then when you lower your main volume from 100, to lets call it 50, effectively the 1 goes to .5. its just not displayed.

Thank you @slhck for your help.

You can do this with Volumouse, which is designed for controlling the volume with custom methods (like the mouse wheel) but happens to let you define the number of steps, which accomplishes what you want.

See related question here.