The sound boxes came today. Hooked one up to my trusty old MRC TechII 2500 and guess what......didn't work. Holy Dissappointment Trackman! Time for a phone call to MRC. Turns out the circuitry in the older MRC transformers is not filtered enough for any of their sound units. Ya gotta spend more money to get things to work. Planned would you say? Fortunately I have a new MRC280 which MRC tech support said would work.
I hooked it up and eureka! I have N scale sound! It's cool! There is a choice of whistle sounds and bell rates along with syncro chuff that is adjustable. The volume is adjustable too. There are all sorts of controllable sounds like hiss, flange squeal, pump, etc. This unit works with both analog DC and DCC.
Mounting the speakers under the table gives an overall impression of surround sound. Considering that I will run the N in DC and that it is almost impossible to get sound in an N scale Shay, I'm glad I bought these units.