The latest firmware release for the MyLocoSound steam board has a new whistle that varies in pitch when played. That, coupled with the fact that It is "Playable"; i.e. it will sound for as long as you hold down the button on your R/C transmitter, makes for a much more realistic sounding chime steam whistle. The basic pitch of the whistle is still user tuneable via the IR Remote, which allows you to choose the sound you like best.
When programming your steam card, you will most likely want to use the "Chime Whistle"; button 9, option 2 using your IR Remote. Most U.S. customers will also like the "U.S. Signal" control mode; button 6, option 3, which allows for a playable whistle while stopped, and a grade crossing signal when the loco is running.
Your "Universal Sound Card" can be upgraded for a nominal fee of $15.