For many when confronted with the terms dBFS, dBu, +4/-10, VU, etc their eyes gloss over. Without understanding a few simple concepts, integrating your DAW with external hardware can be a game of trial & frustration.
To properly drive & take full advantage of hardware in the analog realm, you need to 1st understand what signal level the device is designed to receive. This is when dBu comes into play.
- dBu – (dB in reference to 1 mW at 600 ohms, equal to 0.775 V) All you really need to know is this is a measurement standard for audio signals.
Most professional audio gear is made/calibrated to function in a +4 dBu = 0VU environment. This means when a +4 dBu signal hits the hardware input, it will read 0 VU on the hardware’s VU meter.
- VU – Unit of measurement originally developed in 1939 by the combined effort of Bell Labs and broadcasters CBS and NBC for measuring and standardizing the levels of telephone lines.