Douk Audio VU56C 56-Bit Level Meter, LED Music Spectrum, Stereo Sound Indicator, Audio Display

It works well and offers different modes for how the lights react. I like it.

The Good:Nice looking display that's bright and has 3 colors to show different signal levels (green, orange, red).Very responsive. There are adjustments for how fast it responds, how long the peak holds, etc. It works very nicely once adjusted a bit for your taste.The Bad:As other reviews indicate, this unit produces audible noise, even when using a Y cable to feed this meter and not receiving any return audio back from the meter. It sounds like power supply noise and it's being fed back via the signal cable. I tried a transformer to isolate it, which didn't work. I tried 4 different USB power sources which had no effect. The volume of the noise is pretty low. But if your system is turned up somewhat loud, you can clearly hear the noise when nothing is playing and sometimes in between musical phrases.The Mediocre: The stand to mount this vertically is held by friction. It falls apart almost every time I move it. Not a big issue, but not great.I was considering returning this because I don't want noise in my system. Then I decided to try one more thing: I hooked up a mixing board between my stereo (audio output) and the input to this meter. This worked. The meter gets plenty of signal and the circuitry inside the mixer isolates the signal enough to not feed noise back into my stereo any more. It's silly that I'm using a several hundred dollar mixer for this purpose, but it does work.Tech note: I was able to get a full scale on the meter by adjusting the gain almost all the way up. I measured the difference between the top LED and the first LED at the bottom that indicates signal. The first one starts at about -26 dB. So that's the full range of this meter, which isn't bad.Only recommended if you don't care about a small amount of noise at mid to high playback volumes. Or you are willing to do something crazy like I have done.

Couldn't get it to work.

It works for radio

This unit is advertised with a peak input rating of 1 volt PtP (line level). It will not operate correctly with out a preamp placed in front of it, with the gain set to nearly 2 volts PtP!Once driven hard enough, the display does do what they say it does. Unfortunately, the included instructions are very vague.

Noise and hash are produced by this meter. It's so bad that it renders it unusable, at least as a pass-thru, which it is supposedly designed for. Even when the audio is split, and not used in pass-thru mode, it still managed to produce grunge on the attached INPUT audio! Unusable in any of my applications.

I have bought 4 or 5 of these in the past and they were great! Recently I needed another one and the quality is bad. I returned one and the replacement was not much better. I believe a grounding issue. I switched power and cables. It’s workable but disappointing. This model doesn’t even appear on their website. So I’m guessing it’s farmed out and quality control is down. Sad I now need to find something else

Looks cool, tried it with a few different devices doesn't work consistently with everything. Definitely need to fiddle around with it a bit to achieve the desired results to my liking