how the dat file should be writen to make a vehicle having sound?
From the en.wiki:
Quote
Sound: Can be either a number or a filename (which must not begin with a digit).
- A negative number (e.g. sound = -1) will cause no sound to be played.
- A non-negative number n (e.g. sound = 5) refers to sound[n], as indexed in pak_dir/sound/sound.tab.
- A filename (e.g. sound = engine-start-diesel-0.wav) refers to a wave file located in pak_dir/sound/.
To clarify... -1 is default when not specified and numbers are deprecated, so the preferred way of adding sounds (if present at all) is simply writing in dat file
sound=somefile.wav
and putting the corresponding sound file to pak128/sound (change according to target pakset).