The term 'stereo knob' refers to a type of control found on many audio systems. It is composed of four components: TREBLE (6 letters), BASS (4 letters), TONE (4 letters), and BALANCE (7 letters). The TREBLE and BASS knobs are used to adjust the high and low frequencies of the sound, respectively. The TONE knob is used to adjust the overall sound quality, while the BALANCE knob is used to adjust the relative volume between the left and right channels. Finally, the volume control knob is used to adjust the overall volume of the system.