Audacity will also let you slow down without loss of pitch, however, it's interpolation algorithm (which "fills in" the data between sample points) isn't as smooth as ASD program. Once a song has been loaded, Audacity has three features in it's menu for this.
Change Pitch, Change Speed, and Change Tempo (see menu image)
Change Pitch allows you to easily change pitch without changing the tempo from one key to another in half steps, change frenquency, or change pitch in percentage. This is useful if you have a C accordion and the song is in a D key. (see popup screen)
Change Speed allows you to easily change the pitch AND the tempo together (similar to slowing down a tape or speeding up a record). You can change both by changing the percentage of speed up or speed down. (see popup screen)
Change Tempo allows you to easily change the tempo without changing the speed. You can change the tempo as a percentage of the speed. This is useful when you're trying to learn a song and need it to "slow down" without changing anything else. You are limited by how much you can do this before the quality is degraded. (see popup screen)
Awesome! Thanks for that primer, Wade. I mostly use Audacity to change pitch. I also have ASD - which is very good for changing tempo. That is sort of in its name.
The Calcasieu Waltz is proving to be not . It's just gonna take work