The Book of Audacity

Compress Dynamic Range

This is a dynamic range compressor, not to be confused with file compression. Dynamic range compression is commonly thought of as “make the loud bits quieter and the quiet bits louder.” Most compressors only reduce gain; they narrow the dynamic range by attenuating the louder parts so that the range between the soft and loud parts is reduced. It is overused and abused in commercial recordings, which is a shame because it is a useful effect when it is used carefully and with good purpose. My preference is to use compression as little as possible, because I think many “fixes” done with compression are better worked out during recording, with the Amplify or Normalize effects, or with the Envelope tool.

You can use compression ...