I can do it by ...
Selecting the video clip
Hold shift key down
Place cursor on audio line in the clip, until the cursor turns into a double arrow.
And.. drag up or down with the mouse.
This will make the complete audio volume go up or down at same amount for the entire clip.
This is kind of difficult to get precise settings.
I'm look ing for a way to do the same thing by typing in a db number, and haver it effect the entire clip at once.
Any other method seems to make the volume adjust in the spot where the cursor is placed. Requiring me to make more than one cursor position to get the entire clip adjusted. Ageing Gracefully