Clarity xl40d User Manual page 12

DCP: Tone Settings
XL40D Training
The XL40D offers four different tone settings to provide an experience that
may be customized to fit a specific users need. The illustration above
shows how the four settings relate to each other and the amount of
amplification they give to the different frequencies of sound.
The best way to choose between the settings is to listen to them all and
decide which one provides the best telephone conversation experience.