Gain Staging and Loudness Basics: Making Sense of dBFS, LUFS and True Peak
"My mix sounds quiet for no obvious reason" and "the mastered version came back sounding completely different in level" are two of the most common complaints in production. The root cause is often neither the compressor nor the EQ settings; it's a gap in understanding the level signals run at through each stage (gain staging) and how the loudness of the finished track actually gets measured (loudness).
This guide starts with the units involved, works through gain staging inside a DAW, and finishes with LUFS and True Peak, the two numbers that matter most once a track heads toward streaming.
dBFS vs. dBu
- dBFS (dB Full Scale): The reference unit for digital audio. 0dBFS is the absolute ceiling a digital system can represent; anything above it clips. The meters in your DAW are, almost without exception, reading dBFS.
- dBu: A voltage-referenced analog unit (0dBu ≈ 0.775V), used to describe the line-level output of hardware gear (commonly around +4dBu as a nominal reference).
Because digital and analog use fundamentally different references, you can't directly translate "proper analog gear level" into a dBFS reading. Inside a DAW, it's enough to keep track of how close a signal is sitting to 0dBFS.
Proper Plugin Input Levels and Headroom
Not all plugins react the same way to a hot input. Some digital processors handle signals close to 0dBFS cleanly, while others, especially plugins modeling analog gear, replicate the behavior of the hardware they're based on and can distort more readily than the original hardware if you overdrive them.
The general practice, then, is to keep meaningful headroom (the space below 0dBFS) at every stage of a mix. As a rough guideline, keeping individual track peaks around -6dBFS and mix bus output peaks around -3 to -6dBFS tends to leave enough room for mastering and limiting downstream. These are starting points, not fixed rules — the right numbers shift with the material and genre.
LUFS (Integrated / Short-Term)
LUFS (Loudness Units relative to Full Scale) is a standardized measurement that weights a signal to approximate human perception of loudness. Where dBFS reports an instantaneous signal level, LUFS integrates over time to describe perceived loudness.
- Integrated LUFS: The average loudness across the entire piece, from start to finish. A single number describing how loud the track feels overall.
- Short-term LUFS: Loudness measured over a rolling ~3-second window, useful for seeing how the perceived loudness shifts within the track.
A useful way to keep the two straight: Integrated tells you "how loud is this track overall," and Short-term tells you "how loud is it right now."
What True Peak Is
True Peak estimates the inter-sample peaks that appear when a digital signal is converted to analog, or run through lossy formats like MP3 or AAC. A DAW's standard peak meter only reads the actual sample values, so it can show a signal sitting safely under 0dBFS even though the reconstructed waveform briefly exceeds 0dBFS between samples once played back or transcoded, causing clipping that never showed up on the meter.
For anything headed to streaming or broadcast, using a meter or limiter that reports True Peak, not just sample peak, is the way to catch this before it becomes audible distortion downstream.
How Streaming Loudness Normalization Works
Most music and video streaming services apply loudness normalization: they adjust playback so that a track's Integrated LUFS lines up with a target value, reducing the perceived volume difference between tracks.
As a rough figure, targets around -14 LUFS are commonly cited, but the exact number varies by service and is subject to change, so treat any specific figure here as a general guide rather than a fixed spec — check each platform's current documentation if it matters for your release. What matters more than the exact number is the underlying logic: pushing Integrated LUFS higher than a service's target gains you nothing, since normalization turns it back down anyway. It's usually a better trade to manage True Peak carefully and preserve dynamics than to chase loudness for its own sake.
Putting This Into Practice
The gain-staging mindset shows up inside individual plugins too. AIDE AUDIO GE-1 Gravity Engine's AUTO GAIN feature is one example: put the kick in the side-chain and press LEARN, and GE-1 sets the bass level automatically, referenced against the kick. Multiple bass tracks land at a consistent loudness without manually re-matching gain on each one.