ABSTRACT
An expander is said to make quiet signals quieter. The ratio, just like with compressors, is expressed with the input:output notation. We can see from Figure 19.2 that with a 1:2 ratio, 20 dB fall below the threshold for input signals results in 40 dB fall for output signals. Visually speaking, the portion of the signal below the threshold is stretched downward to be made quieter. It is interesting to note that with the 1:100 ratio the transfer function of the expander looks like a gate. Indeed, a gate is often an expander with a large ratio, and most processors are an expander/gate rather than one or the other. Commonly, we get a
control that lets us dial ratios between 1:1 and 1:100. On some hardware units, a switch will toggle a gate into an expander with fixed ratio, often 1:2.
