The range of human hearing frequencies is:
20Hz - 20,000 Hz (Hz is the frequency unit)
Therefore, the frequency range of the speakers will be defined in this range,the frequency below this range is called infrasonic wave, higher than this frequency range is call ultrasonic.Infrasound and ultrasonic waves are generally inaudible to the human ear.
The equalizer of the combination sound is used to adjust the sound frequency, which will directly affect the sound quality.According to the general rule, the equalizer's bass area is around 100Hz, especially the 100Hz bass is the most elastic.The equalizer's 100Hz slider to raise some if you like the bass when listening to music (such as: drum, bass, etc.).The equalizer's mid-tone region is around 1000Hz(1kHz), especially 1000Hz(1kHz), and the sound of the mid-tone region mainly refers to human voice.The equalizer's high-pitched region is generally around 4000 (4kHz), especially the high-pitched one of 4000Hz(4kHz).