How to Build a Simple Audio Spectrum Analyzer With Adjustable Settings

Simple Audio Spectrum Analyzer with multiple adjustable display, speed, and sensitivity modes for a customizable audio visualization experience.

1. LGT8F328P MCU Board
2. 128x64 LCD Display (ST7920 chip)
3. Resistor 10k ohm
4. Resistor 4.75k ohm
5. Trimmer Potentiometer, 10 kohm
6. Pushbutton x 3

An audio spectrum analyzer is an electronic device or software tool that measures and visually displays the frequency spectrum of an audio signal. It shows the different frequencies present in the signal and their respective amplitudes, typically on a graph with frequency on the horizontal axis and amplitude on the vertical axis. In today's video, I will present you with a very simple way to create an audio spectrum analyzer that, despite its simplicity, has many possibilities for adjusting various parameters directly via buttons, without making any changes to the code.

I got the initial idea from a project on the rcl-radio website and decided to expand the original project with more features. The device uses LGT8F328P which is compatible with Arduino Nano 3 and is significantly cheaper but also with better performance.

For support in Arduino IDE for LGT8F328P, we need to enter the given link (https://raw.githubusercontent.com/dbuezas/lgt8fx/master/package_lgt8fx_index.json) in File - Preferences - Additional Boards Manager, and then in Tools - Boards Manager we install this microcontroller.

This project is sponsored by PCBWay . From September 1st 2025 to 31st Januarry 2026 PCBWay organize the 8th Priject Design Contest. All interested participants can compete in three categories: Electronic Project, Mechanical Project or AIoT Project. The best projects will receive valuable prizes in cash, value cupons and developement boards. Don't miss this unique opportunity and submit your project as soon as possible. PCBWay has all the services you need to create the project at the Best price.

As I mentioned earlier, the device is extremely simple to build and consists of only a few components

- LGT8F328P MCU board

- ST7920 chip LCD display with a resolution of 128X64

- and two resistors

As for the code, it is designed in a way that allows you to easily change many more parameters. For example, The experimental Auto Gain option is very intuitive and works flawlessly, optimally adjusting the bar movements regardless of the input signal strength.

Now let me explain the functions of this spectrum analyzer. When turning on the device, three letters can be seen on the top right of the screen. They sequentially display the current MODE of each button, and are changed by pressing the corresponding button.

- Button 1 cycles through 4 display modes:

Normal: Standard bars

Peak Hold: Bars with peak indicators

Falling Dots: Dot visualization

Mirror: Symmetrical display

- Button 2 cycles through 3 speed modes:

Normal: Standard falling speed

Fast: Quick response

Slow: Slow falling with random elements

- and Button 3 cycles through 3 sensitivity modes:

Normal: Default gain

High: More sensitive (lower gain)

Low: Less sensitive (higher gain)

And finally a short conclusion. This project showcases a simple yet versatile audio spectrum analyzer built with the LGT8F328P microcontroller, offering multiple adjustable display, speed, and sensitivity modes for a customizable audio visualization experience.