Measure Integrated LUFS and LRA in Audacity

Measuring integrated LUFS (Loudness Units relative to Full Scale) and Loudness Range (LRA) is essential for preparing audio for streaming platforms, podcasts, and broadcast standards. This guide covers how to analyze both metrics within Audacity, explaining how to install and apply compliant measurement tools, interpret the resulting data, and ensure your mix meets modern dynamic standards.

Understanding Integrated LUFS and LRA

• Integrated LUFS: Measures the overall average perceived loudness of an entire audio track from start to finish, filtered to reflect human hearing sensitivity. Standard targets include -14 LUFS for music streaming services like Spotify and YouTube, and -16 LUFS for podcasts.
• Loudness Range (LRA): Expressed in Loudness Units (LU), LRA quantifies the dynamic difference between the softest and loudest passages of a program, excluding extreme outliers like silent gaps.

Setting Up a Measurement Tool in Audacity

Audacity includes basic loudness normalization, but detailed readouts for both Integrated LUFS and LRA require an ITU-R BS.1770/EBU R128-compliant meter plug-in (such as the free Youlean Loudness Meter VST or dpMeter).

1. Download a compatible VST or VST3 loudness meter plug-in.
2. Place the plug-in file in your operating system's standard audio plug-in directory, or run the installer.
3. Open Audacity and go to Effect > Plugin Manager (or Tools > Plugin Manager depending on your version).
4. Locate the meter plug-in in the list, click Enable, and click OK.

Step-by-Step Measurement

Method 1: Using Real-Time Effects (Audacity 3.2 and Later)

1. Open your audio file in Audacity.
2. Click the Realtime Effects button on the left panel of the track.
3. Select Add effect, navigate to your installed loudness meter, and click to insert it.
4. Click on the effect name to open its interface.
5. Hit Play (or press the Spacebar) to let the track run from beginning to end.
6. Observe the display:
   • Integrated Loudness: Shows the total LUFS measurement for the played audio.
   • Loudness Range (LRA): Shows the dynamic spread in LU.

Method 2: Measuring via the Analyze Menu

If using an analyzer registered as an Audacity analysis effect or Nyquist plug-in:

1. Select the entire audio track by pressing Ctrl + A (Windows) or Cmd + A (macOS).
2. Go to the top menu and select Analyze.
3. Choose your loudness measurement tool from the dropdown list.
4. Click Apply or Measure. The tool will process the selected audio and present a report detailing the Integrated LUFS and Loudness Range (LRA) without altering the audio waveform.

Adjusting Audio to Match Target Targets

If your measured Integrated LUFS does not meet your required specification:

1. Select the entire track.
2. Go to Effect > Volume and Compression > Loudness Normalization.
3. Set the measurement standard to perceived loudness (LUFS).
4. Enter your target level (e.g., -14.0 LUFS for streaming or -16.0 LUFS for podcasting) and click Apply.
5. Re-run your analyzer to verify that both the Integrated LUFS and LRA fall within your project parameters.