Hello,
I have a stereo clip (double wav forms) in a track.  I want to lower the volume in a section.  When I try to insert an envelope, the green automation line, only appears in the top wav form or channel.  Would changing this only adjust one channel?  I want the adjustment to work on both wav forms.  Any help would be appreciated.
Thanks,
 

It will adjust both. You only have one fader too. Thus one envelope. 

No, it will work equally on both channels

Thanks guys for clearing this up! I would like to mark this post Solved, but I don't know how.

Just edit the thread title.