A equaliser is an instrument specially designed to enhance or customise the sound of any audio player, mixer or audio device, be it digital or analogue. In this article, we will look at how to make a 5-band passive equaliserIt is simple and can be modified according to our tastes to obtain a fairly complete audio equalisation device.
- 1 resistor of 56 Ω and 1 W.
- 1 resistor of 470 Ω.
- 1 6.8 kΩ resistor.
- 1 10 kΩ resistor.
- 2 resistors of 15 kΩ.
- 1 18 kΩ resistor.
- 1 resistor of 22 kΩ.
- 5 resistors of 50 kΩ.
- 1 capacitor of 1 nF.
- 3 capacitors of 4.7 nF.
- 3 capacitors of 10 nF.
- 2 capacitors of 22 nF.
- 2 capacitors of 47 nF.
- 1 capacitor of 100 nF.
- 1 capacitor of 220 nF.
- audio input and output connectors.
Setting up our passive equaliser
The passive equalisers are simple equalisation devices, which perform their task automatically, efficiently (and depending on the components used) controlling the sound bands to obtain a better sound performance.
Our device is made up of 5 potentiometers that are in charge of controlling the tone of the sound, while a sixth potentiometer will be in charge of controlling the volume.
From the circuit diagram, we can see that this device is made up of parallel control zones integrating small series circuits of resistors and capacitors to equalise the 60 Hz, 240 Hz, 1 KHz, 4 KHz and 16 kHz bands from left to right. It will then be connected directly to a small volume control circuit. Next, we will connect a 56 Ω resistor to the side of the volume control and a 10 kΩ resistor to the side of the first wave control in parallel at the ends of the assembly. We will connect this last resistor to an audio output connector, and the end of the 56 Ω resistor, we will connect it to an audio input connector, and we will have ready our passive equaliser.
It should be remembered that this device does not require any power supply and can be used to improve the sound of your car by operating on low-magnitude signals on amplified audio paths.
We can also modify this circuit to create stereo or multi-channel equalisers by adding a similar circuit for each sound path.