This seems like it is way too complicated for what I want, but it works, and I’m not sure how to simplify it. The volume range is 0 to 1. But in the Megaphone program neither limit is ever reached except by some random accidents. So, I start both the upper and lower volume limits (minimumVol and maximumVol) at 0.5, and continue to adjust them throughout the transmission to reflect the input.