I use Stormys DBSM v1.1. I tried several others too, Capthelms, Das Boot (some different version? sounded different), Pacos Sound mod + other smaller sound mods, but this was the best IMO. I loved ambient subvoices and that something is always happening on the backround... This plus few suitable tracks for Gramophone and a good radiostation. Close your eyes and you're in that sub for real...
Almost