17.2.1 Audio normalization and fairlight meter disagree

With the upgrade to DR Studio 17.2.1 (I believe I skipped 17.2 and went to 2.1 directly) I'm having an issue with either audio loudness normalization or the Fairlight loudness meter. They don't seem to agree on the loudness of audio clips.

The audio is from 32 bit .wav audio files.

On the Fairlight tab of the project settings, I have the target loudness setting at -14 LUFS, with other values left at their defaults (e.g. loudness scale EBU +9 scale, etc.)

On the Fairlight page, the Loudness meter is set to BS.1770-1. "Absolute scale" is not checked.

I've tried two different procedures for normalizing the files, one using the normalize audio levels function using "true peak" method at -1 dBTP. The other I used the normalize audio levels with the BS.1770-1 method set at -15 LKFS.

With either procedure, I expected to then be able to go to Fairlight, reset and restart the loudness meter, play the normalized clip, and get a "short max" reading at -1 db. Instead, it's coming back at about +6.6.

Just as a cross-check, I also tried normalizing using BS.1770-1 set to -14 LKFS, and then expected the meter to give me a "short max" reading of 0 since I also have the project's target loudness set to -14. This didn't work either, I just got a decibel difference from what I tried when normalizing to -15 LKFS.

Is this a bug (and if so how do I know which to trust while it gets fixed, the meter or the normalize?), or can someone explain what's going on here? Many thanks.

I've tried two different procedures for normalizing the files

Are you normalising a single or multiple Clips?

Is the "Set Level" preference Relative or Independent?

With either procedure, I expected to then be able to go to Fairlight, reset and restart the loudness meter, play the normalized clip, and get a "short max" reading at -1 db. Instead, it's coming back at about +6.6.

Short-Term is an "intermediate time scale" and uses a sliding scale of 3 seconds (ungated measurement with an LUFS absolute or LU relative unit), whereas you require a True Peak (dBTP) or Sample Peak (dBFS) meter.

In the Meters panel the Control Room Meter indicates the True Peak measurement and the Fairlight Meter AFX indicates Sample Peak levels.

True Peak.png (57.58 KiB) Viewed 1728 times

tried normalizing using BS.1770-1 set to -14 LKFS, and then expected the meter to give me a "short max" reading of 0 since I also have the project's target loudness set to -14

The Short-Term measurement is generally not applicable outside of short form content (e.g. advertising and promotional material), whereas the Integrated measurement for the entire programme is required.

Loudness Meters.png (50.66 KiB) Viewed 1728 times

Maximum True Peak Level (dBTP):
-1dBTP = EBU R128, AES TD-1004, and Apple Music
–2 dBTP = ATSC A/85, OP-59, Netflix, Spotify and Amazon
-3dBTP = UK DPP, France, and South Africa.

(Integrated) Target Loudness Level: (set in Project Settings > Fairlight)
-16LUFS (Integrated) = AES Recommendation
-23LUFS (Integrated) = EBU R128 (Europe & UK DPP & South Africa)
-23LKFS (Integrated) = Portaria 354 (Brazil)
-24LUFS (Integrated) = AGCOM 219/09/CSP (Italy)
-24LKFS (Integrated) = ATSC RP A/85 (U.S. & Canada), ARIB TR-B32 (Japan), FreeTV OP-59 (Australia & NZ)

LUFS = Loudness Units Relative to Full Scale
LKFS = Loudness K-weighted Relative to Full Scale
Note: -24LUFS = -24LKFS

Loudness Scale: (set in Project Settings > Fairlight)
EBU +9 Scale = metering range = -18dB to +9dB (default)
EBU +18 Scale = metering range = -36dB to +18dB

Short-Term: uses a sliding scale of 3 seconds (ungated measurement)
Loudness Range: measures the variation of loudness on a “macroscopic” time-scale, in units of LU (Loudness Units, where 1LU = 1dB), basically the distribution of loudness within a programme.

EBU R128 Recommendation Further reading:
Loudness Recommendation EBU R128: https://tech.ebu.ch/docs/r/r128.pdf
Specific guidance for short-form content: https://tech.ebu.ch/publications/r128s1
Loudness Metering specification: https://tech.ebu.ch/publications/tech3341
Loudness Range descriptor: https://tech.ebu.ch/publications/tech3342
Production Guidelines: https://tech.ebu.ch/publications/tech3343
Distribution & Reproduction Guidelines: https://tech.ebu.ch/publications/tech3344
Loudness Test Set: https://tech.ebu.ch/publications/ebu_loudness_test_set
Practical guidelines for EBU R128: https://tech.ebu.ch/publications/tech3343

ATSC RP A/85 Further Reading:
Recommended Practice: Techniques for Establishing and Maintaining Audio Loudness for Digital Television: https://www.atsc.org/wp-content/uploads ... udness.pdf

AES TD1004.1.15-10 Further Reading:
https://www.aes.org/technical/documents ... _15_10.pdf