Hold on a second let me make some screens.
EDIT: okay, hope this is what your looking for.
1st hover your mouse over the top left of the auido or video, (where the small blue triangle is) you will see that your mouse icon will change to a quarter circle kinda, and with an arrow pointing to the right.
hold and drag to the right as far as you want.
The more to the right the longer it will take to get the audio/video levels back to normal.
After you pull the arrow to the right, you will see like a thin blue line kinda like a rainbow.
Like this ->
Let me know if you need any more help or if I didn't explain enough.