Tone control is a type of equalization used to make specific pitches or frequencies in an audio signal softer or louder.
It allows a listener to adjust the tone of the sound produced by an audio system to their liking, for example to compensate for inadequate bass response of loudspeakers or earphones, tonal qualities of the room, or hearing impairment.
Graphic equalizers used for tone control provide independent elevation or attenuation of individual bands of frequencies.
Wide frequency range graphic equalizers of high resolution can provide elevation or attenuation in 1/3 octave bands spanning from approximately 30 Hz to 18 kHz.
The most modern analog units use operational amplifiers, resistors and capacitors, abandoning inductors because of their size and sensitivity to ubiquitous electromagnetic interference.