Dr. AIX's POSTS — 23 March 2015


Thanks to a reader’s recommendation, I found my way to a paper about the concept of loudness normalization written by Florian Camerer. It’s from the later part of 2010 but provides a great deal of information about the “loudness normalization revolution!” You can get the article here. It’s called, “On the way to Loudness nirvana – audio leveling with EBU R 128”.

The EBU R 128 recommendation “establishes a predictable and well-defined method to measure the loudness level for news, sports, advertisements, drama, music, promotions, films etc., throughout the broadcast chain, and thereby helps professionals to create robust specifications for ingest, production, playout and distribution to a multitude of platforms.” It was developed and introduced because consumers of audio were bugged by the constant and sudden shifts in loudness between programs. We’ve all experienced it. You’re listening to a playlist on your portable player or broadcast device and suddenly there is a huge increase in overall volume as you move from the quiet tail out of a music ballad to a highly compressed and loudness maximized commercial. The reality is that playlists of music on Spotify, iTunes, Pandora, and YouTube have all suffered the same problem…until “loudness normalization”.

Well the European Broadcasting Union (the EBU) decided to do something about it and the result is the R 128 recommendation. It’s important to understand that this applies to broadcasts and doesn’t actually apply to individual music tracks or even music playlists. The distribution channels mentioned above are the ones that are implementing “loudness normalization” to smooth out their playlists. This idea is what has Bob Katz and Ian Shepherd so excited that they’ve written articles about the end of the loudness wars. I agree that it’s a step in the right direction but I’m not seeing it as a major step forward…at least not yet.

Let’s consider what the author of the paper calls, “one of the most fundamental changes in the history of audio in broadcasting: the change of the leveling paradigm from peak normalization to loudness normalization.

First, let’s consider what loudness is. “Loudness refers to the perceived strength of a piece of audio (music, speech, sound effects etc.). The loudness depends on the level, frequency, content and the duration of the audio, amongst other things.” One of the major roles of a mastering engineer is to make sure that all of tracks on an album are the same loudness…the listener should be able to jump from any moment in the program to any other moment in the program and not have to make any adjustments to the playback volume on their AVR. To achieve this goal, a mastering engineer has a number of tools and techniques at his or her disposal. You can simply turn up any tune that is perceived as too quiet and/or lower the loudness for any tunes that are perceived as too loud.

Over this past weekend, I mastered a wonderful new recording of Paul Horner singing 11 of his best tunes (he was a major songwriting collaborator of Peggy Lee) while accompanying himself on solo piano (I wrote about the session some months ago…read here). We recorded the project in real HD-Audio, but I did the mastering for the CD version. The first tune is a solo piano selection and contains a number of very loud moments. However, the rest of the tracks include Paul’s singing and are therefore lower in overall loudness than the instrumental opener. What was I supposed to do? I could lower the amplitude of the opening number but then the relative balance between the rest of the tracks would sound odd. In the end, I compressed the dynamic range of the first tune and turned up the relative volume of the vocal tunes. It worked wonderfully…as long as you experience the album in sequence.

But what happens when an individual tune (with plenty of the original dynamics left in tact) is isolated from the album and played individually? It’s going to sound wimpy against the rest of the songs in a playlist. Imagine hearing a Tony Bennett track just prior to one of Paul’s (he wrote a number of tunes that Tony sang BTW), the perceived loudness between the two would be objectionable.

The EBU R 128 recommendations takes care of the problem by “normalizing the loudness” of the two tunes resulting in them sound very similar in overall amplitude. Problem solved, right? No sadly…it’s not.

To be continued.

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About Author


Mark Waldrep, aka Dr. AIX, has been producing and engineering music for over 40 years. He learned electronics as a teenager from his HAM radio father while learning to play the guitar. Mark received the first doctorate in music composition from UCLA in 1986 for a "binaural" electronic music composition. Other advanced degrees include an MS in computer science, an MFA/MA in music, BM in music and a BA in art. As an engineer and producer, Mark has worked on projects for the Rolling Stones, 311, Tool, KISS, Blink 182, Blues Traveler, Britney Spears, the San Francisco Symphony, The Dover Quartet, Willie Nelson, Paul Williams, The Allman Brothers, Bad Company and many more. Dr. Waldrep has been an innovator when it comes to multimedia and music. He created the first enhanced CDs in the 90s, the first DVD-Videos released in the U.S., the first web-connected DVD, the first DVD-Audio title, the first music Blu-ray disc and the first 3D Music Album. Additionally, he launched the first High Definition Music Download site in 2007 called iTrax.com. A frequency speaker at audio events, author of numerous articles, Dr. Waldrep is currently writing a book on the production and reproduction of high-end music called, "High-End Audio: A Practical Guide to Production and Playback". The book should be completed in the fall of 2013.

(18) Readers Comments

  1. I’ve been describing how BS 1770 and R128 are going to help the loudness war issue, several times in comments on your blog, Mark.

    If radio stations start using R128, and TV broadcast advertisements, including adverts for music and concerts, and Apple Master Quality works out at about -16 LUFS, then we are on our way.

    • I recognize that “loudness normalization” changes the playback experience of broadcast audio but I fail to see how this would motivate the artists/engineers/producers/labels to cease mastering the life out of their releases. I’ve seen no change in the output of sound files and my friend at WB Mastering isn’t doing anything different.

      • With loudness normalization, the super compressed tracks won’t be played back any louder than the ones with dynamic range. In fact, the tracks with greater dynamic range will have higher peaks. I suggest playing around with a loudness normalization plug in to get a good idea of the subjective results. (As much as we can demonstrate what happens mathematically, this is an instance where the psychoacoustics are probably more important.)

        The idea is that when the super compressed tracks just sound flat compared to those that have been less abused – not any louder –, listeners will start preferring the more dynamic content. Mastering engineers will then follow the market. The change won’t happen overnight – you know that change is hard in this industry –, but at least this gives us a glimmer of hope.

        • We’ll see…I have experienced tracks smashed and dynamic tracks. I just think that consumers will appreciate the new fidelity as it exists against what they already are used to. We’ll see.

      • Has anyone ever sat down with the execs who require albums to be loud and just ask them to STOP a explain why they shouldn’t destroy dynamics?

        • The executives that I know don’t care about the sound of the recordings that they make…with the possible exception of Don Was.

      • That’s because America isn’t using R128. What are the LUFS levels of a few of your productions that you think particularly dynamic? (using an R128 meter)

        • I’ll have to get my hands on an R128 meter (can you suggest a source). As I don’t use any dynamics compression, it won’t matter to me what the readings turn out to be. The dynamics of my tracks represent the actual dynamics of received by the microphones.

          • It’s probably available as a plugin for your favourite mixing software. Or maybe built in already.
            Or try this: https://www.klangfreund.com/lufsmeter/

            I think it would matter to you if you start using it as intended.

  2. Sound Forge Pro 11 includes tools for US CALM (-24 dB) and EUR R128 (-23dB) compliance. Here’s a link to an article covering editing for compliance. Also note how at the end of the article Gary Rebholz covers why he believes CALM compliance could put an end to the Loudness Wars.


    Here are some summary statistics for 2 of your tracks.

    Mosaic 96/24 Stereo

    Integrated Loudness (LUFS) -20.25
    Loudness Range (LU) 4.60
    Maximum True Peak Loudness (dBTP) -1.07
    Maximum Short-Term Loudness (LUFS) -17.58
    Maximum Momentary Loudness (LUFS) -14.96

    Bolero 96/24 5.1

    Integrated Loudness (LUFS) -15.98
    Loudness Range (LU) 25.10
    Maximum True Peak Loudness (dBTP) 0.00
    Maximum Short-Term Loudness (LUFS) -7.16
    Maximum Momentary Loudness (LUFS) -4.99

    • Thanks Mark…I’ll take a look at the article and investigate. I need to get a handle on how these numbers translate to numbers that I’m used to.

  3. Hi Mark,

    Take a look at this. Maybe you’d be interested to participate? Don’t know any other details apart from what I’m reading on the site.

    • PS. Seems to me that Ian is really one of the good guys.

      • I think Ian is doing the right things to push for dynamic range. I just don’t see anything changing for the commercial music that we all know and love. I’m willing to joint the fight.

    • I’m going to have to check out all of the details…perhaps.

  4. Match Volumes in Audition provides LUFS values for each track.

  5. Sound on Sound had a fairly detailed article last year about the effects of loudness normalization, and why it’s likely to change mastering practices. I think it does a good job of walking you through the new paradigm with reference to the measurements you already know. There’s a lot there to think about, and the writer isn’t under any delusions that the changes will happen overnight.

    • Thanks for the link…I’m starting to dig into this stuff. The whole LU thing is not a major part of audio engineering for CDs as far as the people I know.

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