tags: music mus-407 electroacoustic dynamic-range

Compander

A compander combines the functionality of a compressor ([compression]) and [expander.md] into one processing unit

• portmanteau of "compressor" and "expander"
• also called Noise reduction (NR) units

Companders are historically used in analog tape recording.

• input [signal] is compressed to allow recording at high levels while avoiding tape saturation
• output signal is expanded on reproduction to attenuate tape [noise.md] and return peaks and [transient.md]s to original level
• result is a low-noise but wide [dynamic range] recording

Some advanced noise reduction schemes use companders in a [frequency]-dependent way.

• signal is split into several frequency bands
• each band is companded separately
• results in more transparent recording with less side effects or artifacts
• continuous glissandi or small irregularities can lead to audible (and potentially unwanted) colorations