If you are installing the aircraft outside the default P3D SimObject structure then you will need to modify the panel.cfg file.
Somewhere in there you will find the entry for the sound gauge and as part of that entry there will be a path the the sound cfg file. Edit the path so it points to your new location.
Somewhere in there you will find the entry for the sound gauge and as part of that entry there will be a path the the sound cfg file. Edit the path so it points to your new location.