This chapter was all about dynamics; what compressors / limiters, expanders, and gates do.
I learned quite a bit about what things I can do with gates, and different kinds of compression to fix a lot of problems that I frequently have with making my own music. For example, using gates to clean up quiet but messy noises, and using side chaining to duck powerful basses from kick drums, can not only help the kick stand out, but also provide a nice bouncy sound to the bass. I have yet to use parallel compression for anything, but I imagine it would be used more as a mastering tool than for a single track. I will continue experimenting.
This chapter is what I was waiting for, for the duration of the course; I can't wait to dive in deeper.