I can't speak for the Bachmann version but the Tsunami's I have been around will give you engine sounds in DC mode. They will also give bell and horn sounds automatically and maybe a few other sounds too. The decoder may need to be programmed to enable the automatic sounds.
That is an issue with the N scale 750 Tsunami. I have some. The DC option has to be selected.
If anyone wants to run sound, get the Dynamis, not the Ez Command.
Below is a link on how to modify the decoder for dual engine simulation.
http://www.mrdccu.com/curriculum/soundtraxx/tsunami.htmSince the Bachmann on board sound decoder by SoundTraxx is the stripped down version, no idea if this will work. It would be nice if someone can verify this.
Rich