How big is the sound of music?
- 21 March, 2013 10:07
When Peter Bliss sits back, closes his eyes and listens to a tune from his 4TB 67,000-song music library, he can almost see where the instruments are on a stage, hear every strum of the guitar, every stroke of a violin's bow, every beat of the drum.
Bliss, who audits insurance companies by day, readily admits he's an audiophile who spends thousands of dollars on his passion and stores his music in lossless digital formats, a growing trend among music lovers.
"The recording quality is almost as important as the music itself," Bliss said. "It's like Ferraris versus Volkswagens. You can get a Beetle and it will take you from Point A to Point B. Some people wouldn't do it in anything but a Ferrari, and others say, 'My 20-year-old Beetle gets me there.'"
Music aficionados are adopting so-called lossless digital music file formats to store albums in a form that's as close to the artist's master recording as possible. The trend is also leading consumers to set up multiterabyte storage systems for their music libraries.
Music purists have long argued that analog recordings on vinyl offer better sound quality than CDs or MP3s, but their stoic loyalty in the face of change was often seen as little more than a nostalgic bias during the 30 years in which digital recordings came to dominate the music industry.
Compressed vs. uncompressed
And, while vinyl record sales have seen a marked uptick over the past decade, they still represent a tiny portion of overall music sales.
More recently, however, audiophiles and high-profile musicians have gravitated toward master-quality music that's playable from a hard drive. That has led to greater use of lossless file formats.
Among consumers, the most popular file format, or codec, is still MP3 -- the compressed file format referred to as "lossy," meaning data is lost in the translation from the original master to the compressed format. Analog audio is recorded by sampling it 44,100 times per second, and then the samples are used to reconstruct the audio signal when playing it back digitally. An uncompressed file on a CD for example, uses 41.1KHz or a 1,411Kbits of data per second (Kbps).
In online music stores such as iTunes, an MP3 music file offers a bit rate of up to 256Kbps. Uncompressed audio files, however, can take up gigabytes of space on a hard drive.
For example, a typical album of songs stored as uncompressed WAV files takes up 640MB of space. The same album of songs in MP3 format can vary in size depending on the quality a user chooses during the ripping process, but in general it will take up about 60MB.
There are other lossless formats beyond WAV (which is short for Waveform Audio File Format), including FLAC (Free Lossless Audio Codec), AIFF (Audio Interchange File Format) and Apple's ALAC (Apple Lossless Audio Codec). These lossless file formats have been gaining popularity because they require less storage space than WAV files, since they first compress the data and then, like a zip files, allow it to be opened and heard in the original, uncompressed format. The highest resolution lossless file, for example, has a whopping-high bit rate of 9,216Kbps, which is 36 times more data than an MP3 file from iTunes offers.
That means these new formats, while still lossless, can save disk space while at the same time offering high-fidelity music playback. For example, an album that takes up 640MB of space in the WAV format would take up about 300MB in the FLAC format.
By ripping music from a CD or vinyl album to a lossless file format, an audiophile can also take control of the format of the digital audio file. For example, the lossless audio format can contain not only the encoded digital music, but also metadata about the music and cover art. And, if the industry develops a better codec, the listener can simply convert the original uncompressed recording to the new codec while maintaining audio quality.
"I think the advantage is the flexibility," said Dan Gravell, who writes the Music Library Management Blog. "By getting the lossless files, you're investing in maintaining your music collection in the future."
"It's definitely been a trend gathering steam in the past few years," he continued. "In terms of the advantages of lossless, the main thing cited is the quality of the sound, and that may or may not be correct."
In contrast, the advantage of lossy file formats is that they take up about half the data storage space on a hard drive.
Major recording artists, such as Neil Young and Dave Grohl, lead singer of the band Foo Fighters, have been publicly critical of compressed file formats and the "significant loss" data, and therefore music quality, consumers are suffering, according to Gartner analyst Michael McGuire. "This is coming as much from artists as from labels who want to sell more copies of the same thing. It does perform differently when you compress it. It's a facsimile of what was originally created," McGuire said.
Hi-def vs. low-def
By Young's estimation, CDs can only offer about 15% of the data that was in a master sound track; when you compress that CD into a lossy MP3 or AAC file format, you lose even more of the depth and quality of a recording. Therefor, McGuire said, "many of the younger bands over the last 10 years or so have been issuing albums in multiple formats."
Young, in fact, created his own digital-to-analog conversion (DAC) service called Pono. Young has tweeted that the Pono cloud-based music service, along with Pono portable digital-to-analog players, will be available by summer.
Young's service would increase the quality, or sampling rate, of the music from 44,100 times per second in a CD (44.1KHz) to 192,000 times per second (192KHz), and will boost the bit depth from 16-bit to 24-bit.
Within file formats, there are many sampling rates (also known as sample frequencies); the higher the sampling rate, the higher the sound quality, or amount of data you can hear. For example, as mentioned earlier, an uncompressed CD has a sampling rate of 44,100Hz (44.1KHz) with 16 bits of data per sample.
The sample rate of a digital file refers to the number of "snapshots" of audio that are offered up every second. Think of it like a high-definition movie, where the more frames per second you have, the higher the quality.
The bit depth is similar to pixels in a photograph. The more bits there are in an area, the higher the resolution. Audio recorded at the common 16-bit depth rate has lower resolution than music recorded at the higher, industry-standard 24-bit depth rate.
Gravell and others argue that the human ear is not sensitive enough to discern the differences between an MP3 file and a lossless audio file format. In fact, some blind tests have shown listeners can't tell the difference, Gravell said.
Hi-def music stores
David Chesky, who co-founded HDtracks.com, disagrees. Chesky, a composer, pianist and a three-time Grammy nominee, started the high-definition music site with his brother in 2008. A few hundred thousand people visit the site each month to purchase music, Chesky said, adding "and we're scaling out: Millions of people in the world are audiophiles."
It's just common sense that the higher the resolution -- the more data that's in an audio file -- the better the sound quality, Chesky said.
"It's not rocket science to see how much more information is in that file," Chesky said. "We're like a 1080p high-definition television set next to a 15-inch black and white. We're for people who listen to music attentively. If you want to listen to music while you're vacuuming, we're not the service for you."
David Chesky, co-founder of high-fidelity digital music store HDtracks, listens to music over a vacuum-tube amplifier.
HDtracks sells songs and albums in multiple lossless file formats, along with the cover art and liner notes in a PDF file download. The music comes in varying resolutions, or sample rates and bit depths -- from CD quality to master recording downloads that take up a gigabyte of capacity and, for obvious reasons, can tax broadband or cellular connections.
The lossless files that HDtracks sells can have several different sample rates. For example, HDtracks sells files in formats that include 96,000/24 bits (which refers to a 96,000-sample-per-second file and a 24-bit rate) and a premium 192,000/24 format.
HDtracks does charge a small premium for its higher quality audio files. For example, Carole King's classic album Tapestry sells for $24.98 in the highest quality lossless file format of 192KHz/24bit. On iTunes, Tapestry goes for $9.99. Other albums in lower resolution formats from HDtracks sell for $17.98.
HDtracks allows users to choose between downloading music in AIFF, FLAC, ALAC and WAV formats. The site also recommends high-resolution player software such as JRiver, Pure Music, or Decibel Audio Player. The software, which basically turns your desktop or laptop into a music server or a digital-to-analog converter, ensures there's no extraneous noise during playback, providing a higher quality listening experience, Chesky said.
Bliss buys two to three albums a week from HDtracks, but he also rips his own music from an extensive vinyl record collection using a $3,000 analog-to-digital converter (ADC). "I clean my record and the first play gets recorded. I load that on my server for convenience purposes," Bliss said.
The most popular music server among audiophiles, according to Bliss, is an Apple Mac Mini. Bliss owns two, and he has two external hard drives on which he stores his music.
Music aficionado Michael Gogesch keeps all 938 of his albums in FLAC files; he's got a 4TB networked storage system that allows him to access his music over the Internet.
Flexibility for the future
Gogesch, who frequents the readers forum of audio magazine Audioholics, agrees with Gravell that there's really no discernible difference in audio quality between an MP3 file, a WAV file and a FLAC file. For him it's all about flexibility.
"If the codec changes in the future, since mine are lossless, I can convert to whatever file format I want, the same as if I just ripped it new," Gogesch said. "To me, that's the biggest advantage. If I want to change a file to any other type of file, I don't need to rerip it, and there's no quality loss when I rip it."
Gravell said that because high-capacity hard drives have become so inexpensive, music aficionados and audiophiles have no qualms about purchasing terabytes of storage for their libraries.
That said, the MP3 format is so wildly popular that it will probably remain the de facto audio format for the foreseeable future. Apple's iTunes recently announced its one-billionth download.
But music aficionados like Gogesch say they won't touch iTunes because it's a "resource hog," meaning it requires CPU cycles to convert the compressed files for play. So Gogesch uses a mobile music player with a hard drive that's got more capacity for his larger lossless audio files.
"On my [smartphone], I use a lower bit rate due to bandwidth considerations. You can go through 2GB a month pretty quickly streaming music," Gogesch said. "MP3 is a great way to lose quality audibly, and if you stream it to a [smartphone] you take another quality hit. Since everything I have is in FLAC, when it goes to my phone, and lower quality MP3, I'm just taking the one quality hit."
Streaming gains ground
However, mainstream music listeners are also quickly moving away from storing their own albums, and instead are signing up for online streaming music services such as Spotify and Mog and even online radio services such as Pandora, which offer higher-than-MP3 quality, from 64,000 to 192,000 sample rate formats.
But as Gartner analyst McGuire points out, just because music starts out in a high-definition format, if the wireless connection loses bandwidth, the song probably won't finish its journey the same way.
McGuire said "some assumption is being made by many West Coast journalists that Internet connectivity is always available." But he points out that just during his walk to work he can't continuously maintain the 3G Internet connection needed to listen to a music service.
Just as streaming music services are catching on, a relatively new high-definition file format is catching the attention of audiophiles. The format, called Direct-Stream Digital (DSD), was created by Sony and Philips for use with Super Audio CDs (SACD). DSD uses a sample rate of 2.8224MHz or 64 times that of a CD's 41.1KHz.
"The trend is toward lossless," Gravell said. "The history of the music industry is almost like a history of the different formats that you're able to buy the music under. At each turn, the music industry seems to try to want to resell us the same music, but under a different format."
Envisioning the evolution of the music retail business, he said, "I can't help but think the future marketing upsell from the likes of iTunes is going to be: 'Download this album in super high quality, such and such format.'"
Lucas Mearian covers storage, disaster recovery and business continuity, financial services infrastructure and health care IT for Computerworld. Follow Lucas on Twitter at @lucasmearian, or subscribe to Lucas's RSS feed. His email address is email@example.com.
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