Hornet VU Meter

Knowing exactly the intensity of the signal you are putting inside your DAW is crucial if you want to use your equipment in its sweet spot, and it's useful to avoid recording your signals to hot.

Every A/D converter from the cheapest one to the most expensive has an analogue front-end before the actual conversion takes place. Since analogue must obey to the law of physics there is just a certain amount of current that you can pass without having distortion in the signal. Usually the manufacturer of converters set the +4 dBu (the "sweet spot" and what is usually shown as "0" on VU meters) to -18dBFS after the conversion, so if the meters of your DAW reads -3dbFS while you record, you are actually driving the input stage of your converters to +15VU, that is A LOT of current flowing through your electronics.

VU meters where the standard metering system before the digital revolution and they still are one of the best way to evaluate the intensity of a signal, their response is intentionally slow to show the perceived loudness of the signal and not the peak.