Steve Cohen made a very useful and informative post about Audio Dissolve Attenuation settings (see link below).
This made me think to post these simple tips:

We're used to adding dissolves by hitting the Quick Transition button  to bring up the Quick Transition dialog window.
However, you can add dissolves in three other ways.

When in Trim Mode, simply enter a duration into the "Transition Effect Duration" entry box (see image below), then hit Enter.
As long as you have enough available handle, a dissolve will be added at the selected transition.
   

When in Effect Mode, select one or more transitions. You can select multiple transitions by holding the Shift key.
Enter a duration into the "Transition Effect Duration" entry box that is at the bottom of the Effect Editor (see image below), then hit Enter.
As long as you have enough available handle, a dissolve will be added.
   

Using the Head Fade and Tail Fade Functions:
  

  

HEAD FADE:
1 - Enable the track(s) you'd like your Head Fade(s)
2 - Place your Blue Position Indicator at the point at which you want the dissolve(s) to end (see picture below)
  

3 - Press the Head Fade button and a dissolve(s) will be added as seen below:
  

TAIL FADE:
1 - Enable the track(s) you'd like your Tail Fade(s)
2 - Place your Blue Position Indicator at the point at which you want the dissolve(s) to begin (see picture below)
  

3 - Press the Tail Fade button and a dissolve(s) will be added as seen below:
  

  

NOTE: The Head & Tail Fade functions will also work between segments.

Steve Cohen has a great post about audio dissolve attenuation settings.
You should take a minute and give it a read:
Read Steve's post at his web site »