Sunday, July 06, 2008

Yo! Turn It Down!


"You listen to these modern records, they’re atrocious, they have sound all over them. There’s no definition of nothing, no vocal, no nothing, just like — static." -Bob Dylan

"Loudness is killing music, and I'm not talking about the 80s Japanese Heavy Metal band." You've probably heard some audiophool, musician or music geek say something like that over the past couple years. But what are they talking about, and what exactly is wrong with loudness?

Loudness is actually a somewhat misleading term, because there is nothing wrong with playing music loud (so long as it's not loud enough to cause hearing damage). What is actually going on is that most contemporary pop music is getting all of the dynamic range squashed out of it by means of dynamic range compression. Dynamic range is the difference between the loudest possible undistorted sound and quietest sound that is audible above the noise floor of the recording. Dynamic range compression limits the difference between the loudest and the quietest sounds. Subjectively, compression makes for a louder sounding recording. It is also a practice that is currently being taken to absurd extremes.

Dynamic range compression is not new. Producers of popular music have been using it for decades, and--used in moderation--it is actually an essential tool in producing good sounding pop and rock recordings. But over the past several decades producers, mastering engineers and recording artists have engaged in a race to create the loudest possible sounding CDs (the so-called "loudness wars") and in doing so have severely restricted the dynamic range heard in today's popular music recordings. This was probably in part a result of the advent of the CD changer. No one wanted their CD to be the quietest one in your CD changer, so we inevitably got louder and louder CDs (and now digital music files as well, because no one wants their song to be the quietest one on your iPod either).

Here is a visual representation of an R.E.M. track, "(don't Go back To) ROCKVILLE" recorded in 1984 and released on CD in the mid-to-late 80s. The dark blue lines represent the peak sound levels at varying points across the recording. The top and bottom of the light-blue area represents the loudest possible point attainable on a Compact Disc. So the closer the blue lines are to the top and bottom of the diagram, the louder they sound. During the 1980s, R.E.M.'s music was exceptional, but in terms of peak levels and dynamic range, this recording is pretty typical of the era.

R.E.M. - "(don't Go back To) ROCKVILLE" CD (1984)

Notice how the mastering engineer chose to leave some "headroom" at the top and bottom, and not push the sound levels to their maximum possible level. From an audio engineering standpoint this is a good practice because your CD player will sound its best when it is not pushed to the limits of its performance abilities. This is no different from the way your car engine runs more smoothly at 55 mph than 135 mph. Technically, it may be able to go that fast, but it's best not to push it that hard. Notice also how there is a decent amount of dynamic range in the recording, not all the lines are at the same level.

Now take a look at a track from R.E.M.'s most recent album, Accelerate. The mastering engineer chose not to leave any headroom--the loudest points are exactly at the maximum limit allowed by the medium. What is more, there is relatively little dynamic range, because everything has been pushed toward this limit. The result is a recording that might sound good in a high noise environment like an automobile, but will sound fatiguing and drained of life on a decent quality stereo system. This is what Dylan is talking about when he says recent popular recordings sound like "static," pushed to these extremes the music starts to take on the quality of white noise.

R.E.M. - "Living Well Is The Best Revenge" CD (2008)

Ironically, while digital-to-analog converters, CD players and other digital gear have gotten substantially better over the past twenty years, the typical CD sounds worse than ever. It's also ironic that despite the fact that R.E.M. just produced the best set of songs they have in decades, Accelerate has been sitting around my house largely unplayed after the first couple of times I listened to it. Have I chosen not to play it because of it's relative lack of dynamic range? It's tough to say for sure, but I suspect it's a factor.

I'm not trying to pick on R.E.M. here, they are simply following what has become standard industry practice among both major and independent labels. Take a look a this track, "Star Sign" from Teenage Fanclub's 1991 release Bandwagonesque on Geffen records. As with the early R.E.M track, the mastering engineers left some headroom and dynamic range in the recording.

Teenage Fanclub - "Star Sign" CD (1991)

Now take a look at a track from Man-Made, Teenage Fanclub's 2005 release on the independent label Merge. The dynamic range has been compressed out of this recording at least as badly as on a typical contemporary major-label release.

Teenage Fanclub - "It's All In My Mind" CD (2005)

Man-Made is another album that made a favorable first impression. I thought it contained a batch of good songs, in many ways the equal of the more popular material on Bandwagonesque. But I haven't listened to it often after my initial purchase several years ago.

One of the worst sounding recordings I've heard recently has to be Bruce Springsteen's most recent release, Magic. Looking at this track I understand why. Every bit of life has been squashed out of the recording by dynamic compression. The result is like Phil Spector's "wall of sound" taken to a near unlistenable extreme. Where Spector's wall was impressive and imposing, Springsteen's is merely impenetrable. It's a pity really because again it's a strong batch of songs, especially this one, "Livin' In The Future."

Bruce Springsteen - "Livin' In The Future" CD (2007)

Now you might say, "Sure, but Springsteen has always utilized that compressed 'wall of sound' approach, it's part of his artistic aesthetic." This is true to a limited degree, but take a look at his classic track "Darkness At The Edge of Town" from 1978 for comparison. The relatively large amount of dynamic range apparent in this recording relative to "Livin' In The Future" gives the recording some room to breathe, and allows the drama of the song's narrative to unfold before the listener's ears.

Bruce Springsteen - "Darkness At The Edge of Town" CD (1978)

You might be forgiven for thinking Springsteen's recordings always featured the ultra-compressed sound featured on his latest release if you had only heard Sony's recent remastering of Born To Run. For this release the mastering engineers reduced the dynamic range almost to the current popular standard. No one would have been able to master a recording like this back when Born To Run was initially released on LP in 1976 because of the very real limitations of the vinyl LP format. Pushing the sound levels this loud would have caused the needle to jump out of the groove on a typical turntable. So while technically the CD is capable of better than 30dB greater dynamic range than the vinyl record, the typical popular or rock music LP exhibits far more dynamic range than today's average CD.

Bruce Springsteen - "Born To Run" CD (1975, remastered 2005)

Perhaps all is not lost, as some producers seem to be backing away from the loudness wars. This track from Duffy's terrific debut album Rockferry displays a considerable amount of dynamic range relative to most recent popular music recordings. The mastering engineer still pushes the volume to the very limit at times, but has mercifully left in some dynamic range. The result is an enchanting and relatively good sounding recording.

Duffy - "Warwick Avenue" CD (2007)

Others are doing things the right way. Does Sharon Jones' "100 Days, 100 Nights" make me want to dance because she and her band the Dap Kings are funkier than hell or because the CD hasn't had all the life compressed out of it? No doubt it's both.

Sharon Jones - "100 Days, 100 Nights" CD (2007)

And not every remastering of an older recording gets "modernized" in the manner that Born To Run did. Dennis Wilson's highly recommended Pacific Ocean Blue retains all the dynamic range of the original master tapes, and it sounds sublime.

Dennis Wilson - "River Song" CD (1977, remastered 2008)

Bob Dylan diagnosed the problem pretty effectively. The ultra-compressed recordings that are the current industry standard sound like crap. Their relative lack of dynamic range results in recordings that might grab your attention at first listen on a cheap radio, but are fatiguing and unrewarding in the long-run. Now I've got a quote for Bob: "Physician heal thyself."

Bob Dylan - "Thunder On The Mountain" CD (2006)

6 comments:

Peter Hennig said...

Pete - This is really insightful. Can we have some technical notes on how you did the analysis(i.e. software)? Do you have an analysis an Lp copy v. CD copy of a recently highly compressed mastered record? I'm also curious to what degree compression occurs when a dynamically open recording is ripped? Do you see as dramatic a change? I have seen some of this in the little digital recording I've done, but it's nice to see it organized as you've done.

Funny that you brought up Teenage Fanclub's latest because your experience completely mirrors mine with this record. I imagine if I rip it to Mp3 and play it strictly through the ipod I would actually enjoy it more (i.e.the way it was intended to be played back).

Really interesting to see a concrete basis for why I consider alot of recent releases to be missing an element of musicality.

Pete Bilderback said...

Hey Pete,

I didn't want to get too technical here, but I will be following this up with other posts. I plan to make analysis of some recent CDs vs. their LP counterparts the subject of a future post.

The program I used here is Rogue Amoeba's Fission, which is good for basic editing. I also have Adobe Soundbooth which is a more advanced program, and I will probably use that to take a closer look at some files.

The thing is I usually look at files ripped from LPs, and they never look anything like this. I knew mastering engineers were using a lot of compression these days, but it was kind of a shock to see visually just how badly it is being abused.

dan said...

Pete,

Great post. I was thinking of this issue today as "Darlington Nights" from the Go-Betweens's Oceans Apart CD popped up on my Ipod. It was striking to me how "loud" such a relatively quiet song seemed. The compression issues are certainly leading to some bad sound quality on what are otheriwse excellent records (and Oceans Apart is as good as anything the band ever did, IMO).

Peter said...

Interesting stuff. I'm curious, do you know what algorithm iTunes uses to automatically play every song at approximately the same volume?

I'm talking about the iTunes Preferences > Playback > Sound Check option.

Pete Bilderback said...

I know a little about Sound Check. It doesn't do any sort of compression or mess with your tracks in any important way.

Basically it is nothing more than an automatic volume control for each song. iTunes analyzes each track as you import them and decides what its optimum volume level should be in order to match the other tracks in your library. It doesn't effect the track in any other way.

It can be a good thing if you are running a playlist or on shuffle at work. But, if you're listening to an entire album, it will turn up the volume on the softer songs and lower it on the louder ones. (Again maybe not the worse thing at work, but not the way the artist intended you to experience the album either).

It would be a better option, in my opinion, if it calculated average volume level per album rather than per track. That way the volume of tracks would not change relative to other tracks on the same album. But then it might not be as effective in shuffle mode.

There are various third party plug-ins that claim to do a better job than what is built into iTunes. I used to have one on my computer at work, but it stopped working one time after I updated iTunes and I never bothered to update it.

I don't have any knowledge of the algorithm iTunes uses to calculate what volume setting to pick, but I suspect it's nothing too sophisticated.

All-in-all Sound Check is not perfect, but at least it's benign.

NQG said...

In addition to the boredom (and pain) that amplifying all passages to the max creates, it also creates enormous distortion through the clipping that perforce occurs. One hears this frequently in live sessions of rock bands, created simply by pushing the guitar amps to the max -- and is no more acceptable there -- but the studio compression of all instruments -- and the vocals -- now creates not the wall of sound, but the wall of noise.

I have a criterion I use when there are vocals in the piece: If I can't understand the lyrics, I walk out.