The Overland Alco C425 has a Tang Band T1-1925S module firing down and out the radiator intake grills. That module is my "go-to" for narrow car bodies.
The 3 P&D F3s have old (and no longer available) QSI 2.07 inch "High Bass" speakers firing upwards and out through the dynamic brake air intake and exhaust grills. Speakers are in sealed styrene enclosures filled with fiberglass batting.
All units are Loksound V4L decoders. When setting up the decoders in the consisted F3s, use a LokProgrammer or Decoder Pro to vary the playback speeds of the prime movers and dynamic radiator fans. That makes them sound like 3 separate locomotives instead of one decoder driving 3 speakers. The effect is more prominent in-person than through an external cell-phone stereo microphone.
Not shown in the video: ABA set of Alco FA1s with Tang Band T1-1931 modules. On all TB modules I cut off the mounting tabs which makes them easier to fit in available space.
