Just received the B unit and put it on the track....wow! I think at full volume the sounds might even approach the decibel level of an actual train! LOL!
Thanks again, Alex. I had no intention of getting the B unit until I saw your great videos.
Looks like I was overthinking the whole duplicate sound issue. All I did was enable all sounds on the B unit and turn the master volume switch on the lead A unit all the way down. That got rid of any out of sync duplication of sounds and let all the sounds go through the superior system of the B unit.
Believe it or not, in the attached video I have the sound turned all the way down so as not to wake the neighbors!