Are sound decoders made that have a whistle or what do I need to record a whistle?
From what Ive read the better boards like the Tsunami's in Bachmann offer choices of different horns and whistles to be chosen from your controller. Custom adjustments too.
Most DCC Sound Decoders like soundtraxx, MRC, QSI and ESU have whistles already on the decoder ready to go. Just select a whistle, adjust the volume to where you want it and go. For the ESU sound decoders, you can also download additional sound files for it and using the ESU decoder programmer, and your computer, you can add and remove sounds from the decoder.
All sound decoders will come with at least one whistle (for steam) or horn (for diesels) and one bell sound. Most offer a choice, from 3 up to 15-16. About the only exception I can think of is that at least at one time QSI diesel sound decoders only came loaded with one horn. They made several different horn sounds, but their decoders only had one on them, so you had to specify that you wanted say a 1st generation EMD sound decoder with a "blat" single chime horn, or Nathan P3, etc.