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LUFS Loudness Meter (EBU R128)

Measures EBU R128 loudness: integrated LUFS, true peak dBTP, loudness range, and short-term and momentary LUFS.

Parameters

Parameter Type Default Description
file_path string required Path to audio file

Example Output

Illustrative summary; MCP responses use structured JSON.

$ analyze_loudness mix-v3.wav

Loudness Analysis Integrated: -14.2 LUFS True peak: -0.8 dBTP Range (LRA): 7.3 LU Short-term: -12.1 LUFS (max) Momentary: -9.4 LUFS (max)

What the Numbers Mean

  • Integrated LUFS — The overall loudness of the entire file. Use it to compare renders or check the target in your delivery brief. Streaming playback normalization is separate from a required mastering level.

  • True Peak (dBTP) — An estimate of the reconstructed waveform peak, including peaks between stored samples. Leave the headroom required by your delivery brief and recheck the encoded file when needed.

  • Range (LRA) — A gated statistical measure of short-term loudness variation, in Loudness Units. It describes variation over a program and is less informative for very short excerpts.

  • Short-term — Loudness measured in 3-second windows. The max value shows the loudest sustained passage. Useful for identifying sections that might trigger limiters.

  • Momentary — Loudness measured in 400ms windows. The maximum shows the loudest 400 ms window. This averages many samples and does not measure an individual transient peak.

In Phantom 1.6.0, silence checks examine the channels separately. Opposite-polarity stereo channels no longer disappear from loudness analysis merely because their mono sum cancels.

Example Prompts

Streaming check

Is my mix loud enough for Spotify? Analyze the loudness of master.wav

True peak safety

Check if my master has any true peak issues at master-final.wav

Dynamic range

What’s the dynamic range of my mix? Is it over-compressed?

Pro tip

If the render exceeds your chosen true-peak ceiling, reduce gain or adjust a true-peak limiter, then measure again. Phantom’s processing Limiter is a sample-peak limiter.