How Volume, Bass, Treble works in Audio Amplifier?


Hey, in this article, we are going to discuss how volume, bass, and treble works in an audio amplifier. You have seen every audio amplifier comes with volume, bass, and treble controls knobs. So, from this article, you can learn how volume, bass, and treble are controlled in amplifiers.

Volume, Bass, Treble in Audio Amplifier



Actually, there is an external circuit required to control volume, bass, and treble. Generally, this control circuit is used between the preamplifier and the power amplifier. Here you can see the below block diagram of an audio amplifier circuit.


Audio Amplifier Block Diagram


audio amplifier block diagram, block diagram of audio amplifier



You can see, the audio signal from the microphone or any source is taken and fed to the preamplifier circuit. The main function of the preamplifier circuit is to eliminate noise and distortion. The preamplifier circuit also amplifies the signal to eliminate the gain problem when the signal is given to the power amplifier.

The output signal from the preamplifier is going to the power amplifier through the volume control circuit. The power amplifier amplifies the signal till it can drive a loudspeaker.



The bass and treble control circuit also called the Tone control circuit. Here you can see a simple volume, bass, and treble control circuit.

Volume, Bass, Treble Control Circuit


volume bass treble control circuit, volume control circuit


Volume Control


The volume control is achieved by dividing the input signal. Generally, a potentiometer is used to control the volume means to increase or decrease. In the above circuit diagram, the first potentiometer is for volume control. So you can see there the input signal is fed to the potentiometer, so when we rotate the knob clockwise, the signal will go to the next stage or to the power amplifier but when we rotate the knob anti-clockwise signal will be grounded through the resistor and volume will be decreased. So the main basic principle of volume control in an audio amplifier circuit is controlling the flow of signal current or dividing the signal.


Bass Control


Bass control is achieved by filtering the signal. This means the Bass control circuit is nothing but an electronic filter circuit. Generally, a low-shelf filter is used for the bass control. The filter circuit is made of resistors and capacitors. So we can use a variable resistor or potentiometer to vary the bass as per our requirement. The low-shelf filter circuit modifies or boosts the low end of the frequency spectrum of the audio signal. In simple words, we can say the bass control is achieved by the low pass electronic filter circuit.


Treble Control


The Treble control also achieved by filtering the signal. Generally, a high-shelf filter circuit is used for the treble control. This also made of resistors and capacitors. Here also we can use a variable resistor or a potentiometer to control the treble as per our requirement. The high-self filter circuit modifies or boosts the high end of the frequency spectrum of the audio signal. So, in simple words, we can say the treble control is achieved by the high pass electronic filter circuit.

In modern amplifier circuits, operational amplifiers are used for bass, treble control. Opamp provides more precise control, low distortion, high coverage, etc.


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How Volume, Bass, Treble works in Audio Amplifier? How Volume, Bass, Treble works in Audio Amplifier? Reviewed by Author on 2/24/2021 Rating: 5
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