I figured this out!!! One can replace any HO locomotive with an original DC board and replace it with a new DCC board that is Soundbug ready ''i.e Digitrax DH165AO", as long as it can fit the locomotive. Currently DCC sound decoders only have Steam and Diesel sounds, however assuming you wanted sound for an ALP-44 electric locomotive, you can dowload whistle and bell sound files of a F40PH diesel locomotive and transfer it to an ALP-44 locomoeive, since it sounds the same as an ALP-44 electric locomotive.
Did you check out Loksound sound files? They have several motor sound files, even the GG1.