Hi Chris
Please don't worry about your English - we're a mixed bunch here. Let's see if I can help you.
I don't have Audio Editor but use the Wave Editor instead.
Firstly though you say that you think Power Director should have a function that auto-reduces the volume when someone speaks. Well, that is a fairly complexs process, better suited to music software such as Cubase or Wavelab. But reducing one volume for another can be done. Of course I would argue that fading music out from one track and in from another is the same thing. PD cannot recognise what is music and what is speech.
How this is done in music software, on TV adverts and on radio is a process called "ducking", but better known as sidechain compression. If Audio Editor has this, I'd be impressed.
A compressor, in audio terms make a wave file such that the loud bits are made quieter and the quiet bits louder. So, if you take the side chain off the loudest bits of one bit of audio and feed it into the other, then this "ups" the overall volume. The compressor kicks in and "ducks" the volume of the music track, leaving the perceived volume of the other track, or the voice track to be louder.
So, when you hear the pumping sound in modern music, you now know what does it!
Okay, so what can YOU do in PD?
It will be a bit harder than inserting a compressor, and take a bit more time, but it is possible.
1 - Sort out the timing points where you want the soundtrack to "duck" and the vocals to come in
2 - Take your soundtrack (highlight it) and go into wave editor.
3 - Using your mouse in the wave file window, drag it between the points where you want the sound to fade out. It turns yellow.
4 - In the left hand pane select "Volume Fade" and select how much you want it to reduce by (say, 50%)
5 - Select the range where the vocal talking comes in. This time take the initial volume to be 50% and the ending volume to be, say 50%
6 - Now, fade your music back in.
Note that in the left hand pane are other options such as dynamic range compression etc, but this is the easiest option.
Other answers that you have received such as editing in the timeline are equally valid, but this is perhaps the easier way to do it until you are happier with keyframes.
As this is my first post to anyone else's problems (being a new member) I sincerrely hope this helps you achieve what you want to do, I hope it helps others and I really hope I haven't got anything wrong !! Good luck
Neil B
--------
Neil B
Growing old is compulsory, Growing up is optional.
ASUS H110-plus Intel 16Gb RAM
Intel core I7-6700 3.4 GHz
NVidia GeForce GTX1060
Windows 10
Power Director 13 - up to date version
Photo Director 6 - up to date version
Colour Director 3 - up to date