The CD Is Dead; Loudness Continues
The biggest change from 15 years ago to today is how people consume music. With more than 100 million iPods sold worldwide as of early this year, more and more people are listening to music on the go rather than at their home stereos. Physical media like CDs are on their way out. And yet overcompression continues to plague the music world.
Even though the CD might be in its death throes, most digital music available online was mastered for CDs. Popular formats like MP3, AAC, and Free Lossless Audio Codec (FLAC) merely use data-compression techniques (not to be confused with dynamic-range compression) to reduce the amount of data a song encoded in PCM takes up. As long as the specter of CDs continues to haunt the online world, downloaded songs will still be subject to overcompression.
But the problem doesn't just lie on the production end. If people are listening to songs in a noisy environment--such as in their cars, on trains, in airport waiting rooms, at work, or in a dormitory--the music needs to be louder to compensate. Dynamic-range compression does just that and more. Not only does it raise the average loudness of the song, but by doing so it eliminates all the quiet moments of a song as well. So listeners are now able to hear the entire song above the noise without getting frustrated by any inaudible low parts.
This might be one of the biggest reasons why most people are completely unaware of the loss of dynamics in modern music. They are listening to songs in less-than-ideal environments on a constant basis. But many listeners have subconsciously felt the effects of overcompressed songs in the form of auditory fatigue, where it actually becomes tiring to continue listening to the music.
”You want music that breathes. If the music has stopped breathing, and it's a continuous wall of sound, that will be fatiguing,” says Katz. ”If you listen to it loudly as well, it will potentially damage your ears before the older music did because the older music had room to breathe.”
Some audiophiles find relief by going back to the past. A few musicians still continue to release their albums on vinyl records (in addition to CDs and online formats). Because vinyl cannot support the loudness that CDs can, these modern vinyl releases are much quieter than their CD counterparts. But they are often less compressed as well, and, in some instances, remastered in a way that is as dynamic as albums released in the 1960s and 1970s.
One of the most prominent examples of this is the recent Red Hot Chili Peppers album Stadium Arcadium, which was remastered for vinyl by mastering engineer Steve Hoffman with the intent of providing full dynamic sound. Hoffman is one of the few mastering engineers who have actually refused to take certain jobs because he's been asked to overcompress music. ”[It happens] all the time,” says Hoffman. ”At least once a week.”
But turning to vinyl for uncompressed music might not always provide salvation. In order to save the cost of remastering, record companies might simply take the compressed master of a song, reduce the overall loudness, and place it on vinyl. Katz warns, ”You could take the Red Hot Chili Peppers recording and put it onto vinyl just as it came from CD, and it would sound just as fatiguing. [The only difference is] you'd just have to turn the volume control up because you couldn't get the peak level the same.”
Tearing Down the Wall
Audiophiles looking to the future for relief from overcompression see a cloudy picture. DVD-Audio and Super Audio Compact Disc (SACD) are two high-fidelity formats that were thought to be solutions to the loudness war. Both formats offer not only a greater dynamic range than CD but also higher sampling rates. This allows for frequencies higher than what most humans are capable of hearing to be encoded onto the medium, addressing a common complaint by people who prefer analog over digital because they claim they can hear these frequencies.
DVD-Audio uses PCM encoding that can support 24-bit, 192 kHz stereo sound (contrasted with the CD's 16 bit, 44.1 kHz) yielding 144 dB of dynamic range, 14 dB over the human threshold of pain. SACD, like the CD, was developed by Sony and Philips and uses a form of pulse-density modulation (PDM) encoding branded as Direct Stream Digital. Basically, instead of having 16-bit samples at a frequency of 44.1 kHz, it takes 1-bit samples at 64 times that rate (2.82 MHz). It has a dynamic range of about 120 dB. Additionally, both SACD and DVD-Audio are capable of high-fidelity five-channel surround sound.
Since their introduction in 2000, however, neither format has taken hold. An overwhelming majority of releases have been of the classical music genre, which has generally not been subject to overcompression to begin with. So even if audiophiles wanted to spend upward of $300 for a DVD-Audio or SACD player, chances are they won't be able to buy their favorite popular albums in either medium.
Since music has gone online, the possibility of having high-fidelity digital files remains, and formats such as FLAC are capable of supporting 24-bit audio. Slim Devices, a company acquired last year by Logitech, has created two products--the Squeezebox and the Transporter--that wirelessly stream digital files from a computer or the Internet to high-end stereo receivers. Both are capable of handling 24-bit audio, but the problem, says Sean Adams, former CEO of Slim Devices, is lack of content.
”If we're going to go to higher levels of sound quality, the real problem is actually getting the content out. Right now, unfortunately, the industry has kind of gone backward from CD quality. When MP3 came out, [it was called] CD quality when it really wasn't,” says Adams. ”We've made some improvements since then with better [compression techniques], but it's really a function of people demanding better sound quality. That has to happen first before the [recording] industry's going to start producing it.”
Overcompression, however, seems to be one of the biggest obstacles to overcome. With music being compressed to have smaller and smaller dynamic ranges, the need for the next high-fidelity audio format vanishes. If record companies aren't making use of the full dynamic capability of CDs, then why bother moving to another format with even more potentially unused capability? And with the average consumer being either completely unaware of, or only subconsciously irritated by, the current state of overcompressed music, there is little incentive for sound quality to progress. Consequently, all the potential benefits of higher-quality audio--lifelike dynamic range, greater frequency response, and multichannel surround sound--remain unseen, even though the technology exists today. Audiophiles are forced to return to vinyl and analog recordings that should have been obsolete 20 years ago.
But there might still be hope for getting out of the loudness war. RMS (average) normalization algorithms, such as Replay Gain, have been implemented in many digital audio players and work to bring all songs in a digital library to the same average level. With Replay Gain enabled, songs originating from many CDs are processed and played back at a consistent average level of loudness. This helps listeners because they no longer have to adjust their volume each time they go from one album to another. And while such normalization cannot undo the compression of music (it amplifies or reduces the song in its entirety), it counteracts any efforts that were put in to make one song louder than another, essentially nullifying the loudness war altogether.
Many hope that widespread implementation of technologies like Replay Gain will make record companies see that further and further compression in the name of competitive loudness is a feckless task, and slowly but surely popular music will begin to return to a dynamic, less-compressed state. In fact, many digital audio players have caught on; Winamp uses Replay Gain, and iTunes has its own normalization option called Sound Check, which also works on iPods.
Whether the loudness war can end and give rise to the next generation of high-fidelity audio depends heavily on the attitudes of consumers. Unlike the CD and DVD video, there is no overwhelming industrial push toward the next level of sound quality. How songs and albums will sound will depend entirely on whether or not the listener actually cares about the intricacies of the music.
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