LUFS Meter

Loudness Measurement Plugin

The LUFS Meter plugin measures loudness similar to the human perception of loudness.

In contrast to peak level measurement, loudness measurement (according to ITU-R BS.1770-3, EBU R128) is quite close to the human perception of loudness. That's why many radio- and TV-stations have started using it to calibrate their content. This results in equally loud radio stations and a well balanced TV program: Commercials won't attack your ears anymore.

Features

Multi-Platform, Multi-Channel

Available as VST- and Audio Unit-plugin, in 32 and 64 bit. Ready to be compiled on Linux. Supports any sample rate. Processes up to 24 channels.

Compliant

The LUFS Meter is compliant to the ITU-R BS.1770-1/2/3 and EBU R128 specifications and enables you to deliver loudness calibrated content.

Open Source

The source code is freely available. This allows you to verify the correctness of the measurement. Furthermore you can customize the LUFS Meter such that it exactly fulfills your needs. Or ask for it.

Flexible interface

System requirements

At least Mac OS X 10.4.4 (Intel) or Windows XP.

The different loudness values

I Integrated loudness The actual loudness. Measured since the last reset.
S Short-term loudness The loudness of the past 3 seconds.
M Momentary loudness The loudness of the past 400 milliseconds.
LRA Loudness range The dynamic range of your music. Measured since the last reset.

LUFS = LKFS = K-weighted loudness units with reference to digital full scale.

How to loudness calibrate your audio with the LUFS Meter

Insert the LUFS Meter on your main output, post fader. If it is not possible in your host to insert it after the main output fader, you can put a gain plugin in front of the LUFS Meter. In this case make sure that the main output fader stays at its neutral position (0 dBFS).

Reset the LUFS Meter and play your song from start to finish. Afterwards, the integrated loudness value (labeled with I in the LUFS Meter) tells you the overall loudness of your song.

The EBU recommends (in the EBU R128 document) to adjust the loudness of audio material such that it has an integrated loudness of I = -23 LUFS. Loudness units scales the same as Decibels. Therefore you can adjust the gain according to the difference between your I value and -23 LUFS. Done.

Example:

Your main output gain is set to 0 dBFS. You play your song and the LUFS Meter tells you that it has an integrated loudness of I = -15 LUFS. Therefore you have to lower the gain by 8 dB, i.e. lower it to -8 dBFS. Now your song has an I = -23 LUFS and is therefore loudness calibrated.

More information about loudness measurement

This video presentation by Florian Camerer introduces you to the concept of loudness measurement. So does his written introduction. Loudness measurement has also been a cover story in Sound On Sound recently.

Technical documents and indepth information are available at ebu.ch and at tcelectronic.com.

Release notes

LUFS Meter 0.5.1

2014 05 09

  • OSX: Compatible back to 10.4.
  • Windows: Compatible back to Windows XP.

LUFS Meter 0.5

2014 04 14

  • Implementation of the Loudness Range (LRA).
  • User interface elements for the LRA.
  • ITU BS.1770-3 compatibility.
  • Fixed stability issues in Bitwig (Mac) and Reaper (Windows).

LUFS Meter 0.4

2014 02 21

  • Reworked the preferences pane.
  • Icons added (vector graphics).
  • Redrawing of the loudness history graphs is done simultaneously (one triggering timer instead of one timer for each history graph).

LUFS Meter 0.3

2013 12 12

  • Show and hide history graphs for the integrated, the short term and the momentary loudness.
  • Different colours for the integrated, the short term and the momentary loudness.
  • The momentary loudness bar displays the value for each channel as well as the combined (the specified value of the momentary loudness according to ITU BS.1770) momentary loudness.
  • Reworked standalone-version with a native title bar and a native menu.

LUFS Meter 0.2

2012 09 04

  • Refined core algorithm for the integrated loudness measurement.
  • Preference pane added to the main window (below the reset button).
  • Adjustable size of the loudness bars (which also affects the size of the numeric values).
  • The range of the bars and the history graph can be set.

LUFS Meter 0.1

2012 06 15

  • Initial Release.
  • Momentary, Short Term and Integrated loudness measurement, according to ITU BS.1770 and EBU R128.