Surely you are curious to know what a vu meter or how it works. It may seem strange, but I am sure that on more than one occasion you have seen or used one almost without realizing that it really was one of these devices. And they are present in a multitude of music devices, including mixing consoles, implemented by software in some sound devices such as MP3 players, equalizers, etc.
In this article you will know everything you need learn about the level meter, its applications, how it works, where you can buy one, and also how to build one using Electronic components simple ...
Table of Contents
What is a VU meter?
El vu meter It is a device capable of measuring the volume level in special units that I will discuss later. These devices can be both digital and analog, the latter being the most common today.
A conventional level meter is basically composed of a moving coil or galvanometer with a certain damping. This will be powered by a full wave rectifier that is connected to a line audio through a series resistor. That way you don't need any additional power source, just the power of the sound signal itself.
That way, you can show the voltage variations of the audio signal, allowing the user to see the volume level at all times. They will do it through a needle on a dial if they are analog, or through LEDs if they are digital.
You do not have to confuse the level meter with noise measurement (sound level meter). They are not the same, and the latter use the decibel or dB unit to measure algorithmic jumps in the sound level they are capturing ...
La volume unit VU (Volume Unit) is defined as «The volume indicator shows 0 VU when an output with an internal resistance of 600 ohms is connected, for a sine wave signal of 1000 Hz and an amplitude of +4 dBu.«.
A term adopted for volume measurements related to human perception of audio signal intensity.
Being a device for measuring volume, the level meter has multitude of applications on sound devices. For example, you can find it in some mixers, equalizers, audio players, music equipment, audio programs, and a long etc. So surely on more than one occasion you have had one in front of you and you did not even know that it was called a vumeter.
You could use it to obtain in a more visual way the sound level for a homemade equalizer, to connect it to the audio output of a device that you have mounted, etc. Some even create complex LED compositions as simple decorative elements, so that they light up to the "beat" of the music. The possibilities are quite wide, you decide ...
Where to buy
If you would like to buy a level meter, then you should know that they are not too easy to find in some stores, but you can get one of them in certain specialized stores or online sales platforms. For example, here are some shopping ideas:
- Nobsound, a complex screen to show sound levels when you connect it to an audio output. The screen has a resolution of light elements of 15x15.
- Kongnijiwa, analog high precision level meter.
- 2 meters and PCB to connect to an amplifier output for your projects.
- Stereo level meter with 2x15 LEDs.
- Velleman MiniKits simple LED level meter
- Another alternative similar to the previous one with green LEDs, and yellow and red to mark high volumes.
- Tiamu, simple level meter with an LM3915 chip and LEDs.
Build a homemade level meter
You have various ways to build a level meter in a very simple way. One of them is through an IC LM3914, an LM3915, or LM3916. Two quite popular chips in the world of electronics. In addition to that chip, as you can see in the previous image, you will also need LEDs of the colors you choose to show the volume level visually, and some extra elements such as resistors, potentiometer, and capacitor.
To better understand its assembly, you can use one of these tutorial videos where they explain it step by step:
You also have other options, like this other simple one that uses two channels of LEDs for stereo:
In this other he has employed the three ICs which I have quoted above to check the result in each of them: