I have a VERY long track I use as the background for a talk show. I am trying to fade to a lower volume after about a minute or so and maintain that volume until about a minute or so before the show ends, then fade back up. The Envelope tool seems to be the answer except it automatically places set points about every couple of minutes. My track is 2 hours long & manipulating hundreds of set points is a drag. Is there an easier way to do this?
THANX! 
The envelope tool produces control points only where you click with the envelope tool. http://manual.audacityteam.org/manual/help/manual/man/envelope_tool.html
This is a 2 hour track (just a constant tone in it) with envelope points at 30 minutes, 35 minutes 1:30 and 1:35
Thank you for your quick response. Looks good, however, the many set points did self actuate.
Is there a a way to remove all set points if you screw up. I know you could move them off the scale, but in my case, dozens & dozens are there.
I don’t want to start from scratch here.
THANX! 
I’ve no idea how you managed to do that 
To remove control points from a section, select the part that you want to remove the control points from (could be the entire track).
Select “Nyquist Prompt” from the Effect menu.
Type the following into the text box and run the Nyquist Prompt.
()s
An alternative method to remove all of the control points is to apply the Equalization effect with the controls set to “flat”.
Thank you all for your input!
SUCCESS!!!
Learned a lot with this one.
I’ll continue to review the forum for other issues.
Again, THANX! 
Which is a bug, of course.
Gale