The Loudness Wars and ITU-R BS.1770
Thomas Lund
TC Electronic A/S
Denmark
KBS • Seoul • June 17, 2015
Before BS.1770
Peak Level Metering
Bad for Broadcast
Bad for Music
Before BS.1770
Loudness
Models
Leq(K) is simple
and performs well
BS.1770 Loudness
Power
Gain
Left
Pre Filter
RLB Filter
Mean
Square
0.0 dB
Right
Pre Filter
RLB Filter
Mean
Square
0.0 dB
Center
Pre Filter
RLB Filter
Mean
Square
0.0 dB
L Srnd
Pre Filter
RLB Filter
Mean
Square
+1.5 dB
R Srnd
Pre Filter
RLB Filter
Mean
Square
+1.5 dB
LFE
Currently not used in Loudness Calculations
Works for mono, stereo and 5.1
Sum
Words: LUFS, LKFS and LU
LUFS = LKFS
Unit for absolute loudness level
Compare with [dBFS] for peak level
-23.0 LUFS is the same as -23.0 LKFS
Only the spelling is different
LU
Unit for relative loudness level
Compare with [dB] for peak level
Loudness at Target Level = 0 LU
LUFS and LU
0 LU denotes Target Level
In this example
Target Level is -23 LUFS
Remember: LUFS is the same as LKFS
Meter Example: LUFS and LU
Target at -23 LUFS
0
Program Loudness
LUFS
-4
-8
-12
-16
Use to normalize programs
to a Target Level
-20
Target: -23 LUFS
-24
Measure: -28 LUFS
-30
-36
-42
-48
-54
-60
Ingest
Corrected
0
Program Loudness
LUFS
-4
-8
-12
-16
Use to normalize programs
to a Target Level
-20
A simple gain offset
brings the program
on Target
-24
-30
-36
-42
-48
-54
-60
Ingest
Corrected
Loudness on three time-scales
400 ms
Momentary
Loudness
Short-term
Loudness
3s
Start
Program Loudness
End
True-peak Level
AES 23 Nielsen & Lund, 2003
Part of BS.1770 also
Even in a linear audio system, analog
and digital level is not the same
1
Analog Level:
Black Line
Digital (sample) Level:
Red Dots
True-peak Level:
Grey Lines
2
Use Loudness meter
to set levels
Only use True-peak meter
to avoid overload
Audio Terminology
PLR
LRA
Peak to Loudness Ratio
Loudness Range
Peak level of a program or track
relative to its Loudness, [dB]
Typical Loudness variation
inside a program or track, [LU]
program or music track
system
Headroom
Dynamic Range
Peak handling capability of a system
relative to Target Level, [dB]
Max/min signal ratio of a system, [dB]
Not a relevant term in this context
Audio Terminology
PLR = Height
Headroom = Clearance
Audio Quality
PLR [dB]
7.400 most popular music tracks
Germany, UK, US
18
17
16
15
14
13
12
11
10
9
8
63
66
69
72
75
78
81
84
87
90
93
96
99
Peak to Loudness Ratio 1963 - 2011
Productions below the dotted line rarely sound good on fine speakers
02
05
08
11
Year
Ortner, 2012
Mark Knopfler
British Grove, London
Japan Loudness Status: TR-B32
All programs: BS.1770-3
Target Level: -24 LUFS
True-Peak Max: -2 dBTP
ITU-R WPC6: Extension of BS.1770 to 22.2
US Loudness Status: ATSC A/85
Commercials: BS.1770-3
Programs: Speech level
Target Level: -24 LUFS
True-Peak Max: -2 dBTP
Uncertainty when measuring programs...
Results: Cumulative Uncertainty
[dB]
15
Definition
12
9
Classification
6
3
Measurement
0
Loudness
Speech
[LU]
+8
6
4
ATSC A/85 uncertainties
Definition
Classification
Measurement
2
0
2
4
6
-8
Program
Interstitial
Drama
Interstitial
Film
1.
2.
Count Basie:
Imagine Dragons:
“Mean Old World”
“Demons”
Secret stereo recording
by Bruce Swedien
1959
From album
Night Visions
2012
Each track loudness-normalized to -18 LKFS/LUFS
References
More Info
Karl Küpfmüller (1962).
Edit by K. Steinbuch ,
Springer, Berlin
Nachrichtenverarbeitung im Menschen
Benjamin Libet et al. (1979). PubMed id#427530. Bethesda, MD
Subjective Referral of the Timing for a Conscious Sensory Experience
Rudolf Ortner (2012). Donau Universität, Krems
Je lauter desto bumm! - The Evolution of Loud
Nielsen & Lund. (1999 - 2006). AES 23, 107, 109, 111, 121
Stop Counting Samples and 0 dBFS+ Level
Skovenborg & Lund. (2007 - 2014). AES 123, 125, 127, 132, 135, 137
Loudness Descriptors to Characterize Programs and Music Tracks
ATSC A/85, EBU R128, ITU-R BS.1770, TR-B32
AES 58 June 30 11:00 Prevention of Hearing Loss from the use of
Personal Music Players
End