FLAC, ALAC, and Other Digital Recorded Music Formats


By Daniel McAdam.

Having worked in both the telecommunications field and for the federal government for a good part of my life, I possess an understandable aversion to initialisms. When it comes to appreciation of classical music, I would much rather discuss things like timbre and harmony than I would things like FLAC and WAV. Nevertheless, one does today have to have at least a basic understanding of these and other recorded music formats to know what one can and should listen to on which type of equipment. This struck me recently when I was reading a description of the Moon by Simaudio 780D Streaming DSD (Direct Stream Digital) DAC (digital to analog converter), which stated that the item's MiND (MOON intelligent Network Device) network player supports a number of file formats, including AAC, AIFF, ALAC, FLAC, FLAC HD, MP3 (VBR/CBR), OGG Vorbis, WAV, and WMA-9. Well it should, you think, since the device (pictured) costs approximately $15,000 - but just what are all those formats?

Here's a quick primer. First, understand that we are talking about digital music files. Second, bear in mind that there are three variables by which such files are judged:

  • Bit depth
  • Sample rate
  • Compression (or lack thereof) format

Let's start simply, and say that we're going to download a song from Amazon. According to Amazon, "Where possible, we encode our MP3 files using variable bit rates for optimal audio quality and file sizes, aiming at an average of 256 kilobits per second (kbps)." MP3 stands for MPEG-1 (and/or MPEG-2) Audio Layer III, which doesn't explain a lot; the term comes from the film industry. Amazon says it uses "variable bit rates," so that makes the file MP3 VBR, as opposed to MP3 CBR (constant bit rate, not what you'd normally want for music). MP3 is not lossless, meaning - this is an over-simplification - that in the process of compressing the digitized music to a file that takes up less space, something is lost. How important that "something" is can vary. By the way, instead of simply saying something is not lossless, most techies prefer the term, "lossy."

Next, let's play a compact disc (CD) which is, of course, a round disc containing digitized files. Most compact discs have files with a bit depth of 16 bits and a sample rate of 44.1 kHz. In non-technical terms, that's known as "mucho better than MP3." The only drawback is that the file is a lot bigger. What might have been a 5 MB or 6 MB MP3 file is now something like a 30 MB file. CD files are uncompressed, using Pulse-code modulation (PCM), which was created way back in 1937.

So CD sound is the best, right? Actually, in spite of it's detractors, CD sound is PDG (pretty darn good). But you can't say "best" for a lot of reasons. Some people don't like digital music, period, and they're the ones buying turntables and vinyl records. Additionally, there are digital files one can purchase directly with greater bit depth and larger sample rates, up to 24 bits and 192 kHz. If you automatically assume that bigger is better, then these files would be better. In the real world, there are a lot of factors at work, including the equipment you're using to listen to music and how good your ears are. Most adults can't hear much above 20 kHz. Then, too, there's an argument that playing sounds you can't hear - ultrasonic content - can cause intermodulation distortion. In other words, you personally might get your best listening experience from a bit depth of 16 bits and a sample rate of 44.1 kHz. The source, understandably, can also make a big difference.

Can you rip a CD track and have the ripped file sound as good as the CD? Theoretically, yes, by ripping the track in a lossless format. I usually use FLAC (Free Lossless Audio Codec), and listen to my music via foobar2000, which can be downloaded for free. Most everyone likes and plays FLAC, including Microsoft; the exception is Apple, which only likes ALAC (Apple Lossless Audio Codec), because it has the name Apple in it. Does your iPod play ALAC files? Yes, it does. Does your iPod play FLAC files? No, it does not.

You really don't need to worry about those other formats for listening to music, since they are or have become uncommon, so I'll go through them quickly. AAC (Advanced Audio Coding) is used with MPEG4 stuff, is lossy, and Apple likes it. WMA (Windows Media Audio) is lossy and Microsoft likes it. Vorbis is lossy, free source, and used in a lot of games. WAV isn't really an initialism; it indicates Waveform Audio File Format, and Microsoft likes it. AIFF (Audio Interchange File Format) was developed by Apple in 1988, and is lossless. AIFF files are bigger than ALAC files; some people think AIFF and/or WAV files sound superior to ALAC files.

 

Summary

My hope is that this brief foray into the world of digital music formats wasn't too painful. As noted above, there are a lot of factors that impact the experience of listening to digital music besides compression formats, which is good to bear in mind. When I'm at home, I usually listen to FLAC files that I've ripped from a CD through my budget audiophle system. When I'm in my car, which is always a less-than-optimal environment for listening to music, I listen to MP3 music played from a USB thumb drive. When I'm exercising, I'm usually listening to music in an MP3 format from an iPod.

It's always fun to debate compression formats, digital recordings versus analog recordings, greater bit sampling, and so on, but one should never lose sight of the fact that listening to good music is always a good thing, even during those times when the experience cannot be optimized.

 

 



 

 

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