ESU CabControl and LokSound Installations Group | Here is another Athearn Genesis GP9 installation using a 58921 decoder and a Scale Sound Systems speaker
H0 track - diesel locomotive EMD GP9 Conrail digital with ESU sound: Amazon.de: Toys
Amazon.co.jp: SSI Ltd. esu・esu・ai 4GX – m200r Fast 聴機 CD Type CD Player Only Super Listening System (napoleon Hill/SSPS – V2 system) Motivational : Electronics