Mixing Audio, 3rd Edition

20Expanders

Expanders are very common in mixing environments, although not so common in mixes. Expanders are the opposite of compressors in that they expand dynamic range rather than compress it. Indeed, expanders are often used to expand what a compressor has compressed—a do–undo system called a compander. Apart from being a vital part of noise-reduction systems for tapes, a compander has little to do with mixing. Still, compressors and expanders work on a very similar principle—both are based around the same design concept and share identical controls, most notably a ratio. The fundamental difference between the two is that a compressor affects signals above the threshold, while an expander affects signals below the threshold. If one understands ...