The Loudness Race: the aim of pop music producers to create sounds that are bigger and louder in order to sound “better” on the radio. It’s a sickness, really. Abou talked about it almost a year ago, though unfortunately the site he links to is gone (though you can sort of view it with the Wayback Machine).

One of the major problems that have cropped up in many of the pop music releases in the past 5 to 6 years is level control. I have painfully listened to my step kids CDs and heard the shrilling sounds they conveyed. I wasn’t surprised when I hooked up the CD player’s analog outputs to my oscilloscope and observed levels so high that they were clipping on a consistent basis. One normally thinks of clipping as a power amplifier problem, yet clipping in the digital domain can be just as bad.

I bring this up, because lately I’ve been experimenting with the FLAC audio compression format. It’s touted as having an average compression ratio of 0.5-0.55 (original size * 0.5[5] = new size). When I was converting a CD of Rachmaninov piano concertos, I got between 0.38 and 0.47. Obviously, those are extremely good compression ratios for a lossless encoder. In fact, they are such that I’ve considered buying some extra storage space and having my entire music collection be FLAC. Except I can’t. Because most of my collection is modern, and probably hot as hell. I tried encoding my Boy Hits Car album in FLAC, and got average ratios of 0.75 (that’s bad: only a quarter of the file size was shaved off). At 400 modern CDs, that’s almost 300GB right there, not counting anything else I download.

And yet, when I encoded King Crimson’s In the Court of the Crimson King, I was getting the promised levels of between 0.5 and 0.6. Why? Because that album was recorded and mastered well, just like most recordings of classical music. With the proper levels, FLAC is able to achieve good compression rates. Another album that is supposed to be excellent in regards to this is Tool’s Lateralus according to Wes Lindstrom. In an effort to test my hypothesis about FLAC, I decided to do a rough comparison of rates for a robust classical album (Solti/CSO play Mahler’s 8th Symphony), a relatively tame classical album (Ashkenazy’s performance of some Rachmaninov preludes), Tool’s Lateralus, Opeth’s Blackwater Park, RHCP’s Californication, Oasis’s (What’s the Story) Morning Glory?, Änglagård’s Epilog, and Jethro Tull’s Thick as a Brick. I will average the ratios for all tracks and present the findings, seeing if the compression matched what I thought it would be based on my preconceptions of the mastering. For instance, I expect both classical albums to be excellent, as well the Jethro Tull and to a lesser extent the Änglagård. Opeth will fall in the middle, and Oasis/RHCP will be horrible. All compression is done using FLAC 1.1.2a -8 -V.

Album No. of tracks Mean ratio Whole album ratio
Opeth • Blackwater Park 8 0.680 0.714
Oasis • {What’s the Story} Morning Glory? 12 0.684 0.689
Red Hot Chili Peppers • Californication 15 0.707 0.708
Jethro Tull • Thick as a Brick 2 0.534 0.534
Änglagård • Epilog 6 0.439 0.520
Tool • Lateralus 13 0.540 0.580
Gustav Mahler • Symphony Nr. 8 (Solti/CSO) 16 0.518 0.499
Sergei Rachmaninov • 24 Preludes [Disc 1] (Ashkenazy) 15 0.342 0.337

As you can see from the results, most of my hypothesis was confirmed. Classical music, even boisterous Mahler, compresses extremely well, while modern music does not. Depending on the type of music, a similar approach may or may not be taken in terms of mastering and levels. The Änglagård album, recorded in the the style of 60s prog bands, saw compression rates similar to those touted by FLAC’s coders. Californication, mentioned specifically by Wes Lindstrom for being extremely hot, sees levels at about 0.75. That was 1999: today, most rock/pop albums are that hot. Lindstrom also specifically mentioned Tool’s Lateralus as being well-mastered, and we can see that the main tracks tend to fall in the low 0.6s: not exactly the best I’ve ever seen, but excellent for an album with as many furious moments as it has. Even Mahler’s 8th hit similar numbers at one point.

I’m no expert on the acoustic model, but it doesn’t take a neurosurgeon to figure out that the music industry’s tendency to create extremely loud/hot albums (think of these in terms of the acoustic model) is not only damaging to the quality of the music, but it also defies our ability to compress it efficaciously. When you consider that pop bands essentially record for the radio, it’s really no surprise that most people can’t appreciate the difference between a well-mastered and a poorly-mastered album. It’s also no wonder that people don’t seem to mind listening to mp3s with such low bitrates: these songs were recorded for a lackluster medium, and one lackluster medium is as good as another. Hot mastering steals away dynamic contrast and quality sound. Take heed, producers: give us back our music!

§645 · June 14, 2005 · Tags: , , ·

8 Comments to “The loudness race and audio compression”

  1. rob says:

    Whilst I definitely agree with your post, I’m curious as to why you’d re-rip everything you own as FLAC. Surely you can’t tell the difference between a well-ripped, well-encoded lossy file and the original?

  2. abou says:

    Depends on the file format and what type of music. I can tell the difference – it is how I stumbled upon oggs in the first place.

  3. Ben says:

    In many instances, yes. Naturally, some albums wouldn’t matter much, but I have really nice Sennheiser headphones, so lossy compression can be apparent.

  4. […] As stated before, the tendency to create extremely loud songs suited to radio airplay is a death knell for music quality. To all producers and sound engineers, this is a call to start mixing audio in such a way that preserves dynamics and makes the experience of listening to said music more enjoyable. Not only does hot music just sound bad, but it makes the job of compressing and manipulating that music even harder. Stop it! Just stop it! Ross Robinson, I’m talking to you! […]

  5. ex-music-lover says:

    Now I know why I can’t get my music to sound good. I admit part of it is my equipment, but there are parts of DVD movies that sound flawless and I’m unable to tell that it’s a recording. No point in upgrading if poorly mastered recordings will just sound bad on a better system.

  6. Ge Someone says:

    It is a well know fact that quieter music compresses better in all lossless codecs. It’s just less bits (used).

  7. Ben says:

    But I’m not talking about “quiet.” I’m talking about “hot.”

  8. ronocdh says:

    Very informative post, thank you. This came up on a hit for “Opeth FLAC” because I was researching this very thing! Personally I am going to purchase more space and FLAC all my stuff, I think it’s worth it in the end. ‘Peth heads usually want every bit of quality they can eek out of their CDs, I should think. =) Thanks again!

Leave a Reply