Reference chart
Audio reference levels: dBFS, dBu, and LUFS
Digital meters read dBFS (decibels below full scale), analog gear is specified in dBu, and the two connect only through an alignment convention: SMPTE practice puts -20 dBFS at +4 dBu, EBU practice puts -18 dBFS at 0 dBu. This chart lays out the alignments and the loudness targets built on top of them.
Digital-to-analog alignment conventions
| Convention | Alignment | Full scale (0 dBFS) equals | Where you meet it |
|---|---|---|---|
| SMPTE (US broadcast/post) | -20 dBFS = +4 dBu | +24 dBu | US broadcast plants, most pro interfaces |
| EBU R68 (Europe) | -18 dBFS = 0 dBu | +18 dBu | European broadcast and gear menus |
| Common live console default | -18 or -20 dBFS nominal | +22 to +24 dBu | Digital console I/O specs |
Loudness targets (program loudness, LUFS/LKFS)
| Standard | Target | Applies to |
|---|---|---|
| EBU R128 | -23 LUFS integrated | European broadcast programs |
| ATSC A/85 | -24 LKFS integrated | US television |
| Common streaming normalization | about -14 LUFS | Music streaming platforms (varies by service) |
| Cinema (mix stage practice) | calibrated monitoring, not LUFS | Theatrical mixes at reference SPL |
What this means at a show
Live consoles do not enforce a broadcast alignment, but the conventions still anchor gain structure: keeping program peaks around -18 to -10 dBFS on a digital desk leaves the headroom the analog outputs were designed around, and hands a sane level to broadcast or stream feeds that do care about the standards above.
When a show feeds television or a stream, the handoff conversation is exactly these numbers: what tone level the truck wants (they will say something like "minus 20 tone equals plus four"), and what integrated loudness the delivery must hit. Bars and tone exist to carry the alignment across the wall between two departments’ meters.
Frequently asked questions
What does -20 dBFS mean?
20 decibels below digital full scale, the SMPTE-aligned nominal operating level. Aligning tone at -20 dBFS to +4 dBu means the digital system clips at +24 dBu equivalent, providing 20 dB of headroom over nominal.
What LUFS should a live stream be?
Platform normalization mostly lands music streams near -14 LUFS integrated, while broadcast deliveries specify -23 LUFS (EBU) or -24 LKFS (US). Mix to the delivery spec of whoever takes your feed, and confirm it during the advance rather than after the complaint.
Why does my digital console meter differ from the analog gear?
Different references: the console meters dBFS, the outboard is specified in dBu, and the conversion depends on the interface’s alignment (commonly 0 dBFS = +22 or +24 dBu). Send tone and measure once; guessing costs headroom or noise.