Hi Ildamos. The most direct route is to replace the sound files with softer versions of the same sound.
1. Find "pak.zip" in your TL install folder and open it up with an appropriate archiving software (winzip, winrar, 7zip, etc.)
2. Navigate to the "media\sounds\Character\Mechdwarf" sub-folder and extract the following files:
3. Use your Windows Sound Recorder accessory to adjust the volume of these files to whatever level you want.
4. Put these edited files into a series of folders like this:
where "MainFolder" can be any name you want.
5. Put the "MainFolder" folder into your TL mods directory.
That oughtta do the trick