\SilentHunterIII\data\Sound\Gramophone. I'm sure some or all of the d/ls would include readme files outlining where to place them.
BTW 89 posts in three days. My, you've asked a lot of questions!
To save yourself some time waiting for responses, you may like to try the Subsim Forum "Search" feature, where questions like this one have been asked before. You'll get a quicker response then!
You may also like to peruse the
Silent Hunter III Community Manual where this exact question is also answered.