LED Spectrum Analyzer The low-pass filter is usually placed on the left and the high-pass filter is placed on the right on the display panel. You can experiment with filter selection by changing the capacitance of the capacitors and resistors. Instead of capacitors and resistors for the low-pass filter, you can use an inductor coil (about 500 turns of thin wire).
Compared to other shared LED Spectrum Analyzer circuits, the circuit is simple, easy to make and low-cost since passive filtering is done with a capacitor-resistor combination in the filter stage. You can create a simple LED spectrum analyzer by adding a simple filter circuit to the input of a transistor, integrated vu-meter circuit.
The test video shows a 4-channel LED audio spectrum analyzer.
Filters used in audio input;
source: cxem.net/sound/light/light50.php
