I see some sound decoders that refer to 'modern' diesel sounds and some that mention second generation diesel sounds. Would these all be for locomotives manufactured after the early '60s? What is the audible difference from F units and early Geeps?
I wish more DCC decoder manufacturers had sound demos on their sites. I was able to find these that might help compare various prime-mover sounds:
http://www.soundtraxx.com/dsd/tsunami/index.php?p=tsunamisound.php
I'm still looking for a few sounds I commonly hear from idling NS Dash 9's. Notably a ticking sound made by "spitters", an occasional compressor sound, and a "whoop!" sound. One was idling across the street the other night around 3:00a and I couldn't pull myself out of bed to go record it. :P
The Tsunami GE FDL-16 sounds seem to replicate the spitter portion at least - though the ones I hear are a little crisper, more of a tick than an air spraying sound.