Frequency VU visualiser.


I have made a VU frequency visualiser using a MSGEQ7 chip, WS2812 leds and an arduino. I am pleased with result.

I was hoping you could answer a question on how not to degrade the audio.

Presently, i run one channel (mono) audio into circuit and have no audio output, and i cant hear anything. i know that i have to put the VU circuit in parallel to the audio signal but i am wondering if i need to add any electrical components to ensure that i don't deamplify the audio signal, or add noise, etc.

If i split the audio signal so that it runs to an amplifier and speakers, and also to the VU contraption that i have made, what do i need to do to ensure that the audio is not degraded?

Hope this question is sensible enough to get a reply. I know i should have included some sort of circuit diagram but i trust it is simple enough to 'visualise'.

It would probably help if you say where the audio signal is coming from and what its level is.


Just BTW, Frequency and 'VU' (Volume Units) are completely unrelated.

I have made a VU frequency visualiser

I'm guessing you have built a form of spectrum analyser...
Which displays amplitude (VU - sort of), against frequency...

Try asking some audiophiles about this, it's not much to do with Arduinos as the issue at hand is on the (analog) input side of the MSGEQ7.

Have you actually tried just connecting it in parallel? It shouldn’t degrade the audio. If you find that it does, just add an op-amp buffer.


It won't have any effect (assuming it's wired properly, etc.).

The input impedance of the MSGEQ7 is 1 Megohm which is high-enough to have no effect on a line level or headphone-level signal.

It IS possible to get noise back-into the audio circuits through the ground or power supply when the lights switch on & off but I wouldn't expect that.

BTW - The MSGEQ7 is a [u]spectrum analyzer[/u] chip. It's mis-named as a "Graphic Equalizer" although it may have been designed to be used as a display built-into an equalizer.

...The Arduino has even higher input impedance long as the input is positive. If you feed an AC audio signal the internal protection diodes can clip (distort) the negative half of the signal (or worse). When the diode "kicks-in", the impedance drops to very low, essentially shorting-out the audio. But, the MSGEQ7 is designed for AC audio signals.