Rob,
The best visible example is here:
http://www.litchfieldstation.com/lobby/HODS-ARTR-DSD101LC.htm
You can use a variety of decoders. I recently used a Quantum Revolution with a Kobitone 16mm x 35 mm speaker mounted under the rear fans as described at the link. The sound is nice since the shell creates a nice resonating baffle.
I have installed several decoder types in Athearn RTR's:
1. Digitrax DH165A0 with a SoundBug attached
2. ESU Loksound decoder with the dual 0.63 speakers (quasi small oval arrangement).
3. QSI Revolution
All three have good motor control using back EMF, offer amplification not requiring coupling capacitors (caps are used by Digitrax and QSI as holdup - not coupling) and have nice volume when using proper speaker baffling. I recommend purchasing the programmer for any of these decoders to "tweak" their performance. Many Americans complain about the low volume of ESU horns; the Lokprogrammer is required to adjust the sound sample file volume louder prior to uploading it to the decoder. If the factory volume levels are adequate, you don't necessarily have to buy the programmers.
Currently, Digitrax and ESU decoders allow you to import your own sound samples into their decoders; for example if you record horns at a "sound-off", you can use your horn samples in place of the factory supplied horns. The process is more involved than my simple explanation, but learning the process is not difficult.
Good luck with your project and have fun!
Carl in Florida - - - - - - - - - - We need an HO Amtrak SDP40F and GE U36B oh wait- We GOT THEM!
I recently purchased 2 Athearn RTR GP35 units and was wondering how hard it would be to install sound? Anyone done this yet? They are both DCC plug in equipped, but I'd like to install sound in atleast one of them. If anyone has had success, how tough is it to do? Just getting into the DCC and I have a Digitrax DT400R radio throttle. Also... whats some good realiable decoders to use? I havent opened up any of these units yet, but Im told there's not much room inside.
Thanks!
Rob