04/23/14

Audio: The High-Resolution Revolution

Do you need it and how do you get it?

Just as a great player never stops trying to improve his or her chops, the best recording engineers and audio manufacturers never stop trying to make their products better. That’s why they’re making a big push now with high-resolution audio. The difference is, as the musician gets better you’ll almost certainly hear the difference. With high-resolution audio, the progress is not so clear.

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Korg DS-DAC-100m

High-resolution audio can be defined as any type of digital audio that’s better than CD quality. Now here’s where we have to get a little technical, but I promise to minimize the math.

Giant Steps
For CD-quality sound, an analog audio signal is digitally sampled (i.e., measured and stored) 44,100 times per second. At this resolution, the recording can capture frequencies up to about 22,000 Hz, or cycles per second. To put that in perspective, the highest note on an 88-key piano is 4,186 Hz, although that note also contains harmonics at higher frequencies. Each sample comprises 16 digital bits, or 1s and 0s. There are 65,536 different combinations of those 1s and 0s, so this gives you 65,536 different possible levels. (It’s like if the volume knob on your stereo receiver gave you 65,536 distinct steps instead of the 60 or 80 steps most of them have.)

With high-resolution audio, the signal is typically sampled 96,000 or 192,000 times per second, which means you can record frequencies as high as about 48 kHz (for 96 kHz sampling) or 96 kHz (for 192 kHz sampling). Each sample usually comprises 24 digital bits, so you can capture about 16.8 million different levels.

Some audio experts point out that because of the noise present even in recording studios, and because few adults can hear frequencies much higher than 16 kHz, all that extra resolution is wasted. Audiophiles counter that the sound is better because the filter circuits required for digital recording can be moved up to higher frequencies, further outside the range of human hearing. Pros have embraced high-res; almost all studio recordings are now produced in high-res, then downconverted to make CDs and MP3s.

It’s easy and cheap to hear the difference for yourself, because most high-res audio is delivered through computer downloads. Start at HDTracks.com, which has lots of classic jazz albums in high-res, in most cases dubbed off the original analog master tapes. Find a beloved album you already have on CD—maybe John Coltrane’s Blue Train or Lee Morgan’s The Sidewinder—and buy the 24-bit/96-kHz download for $17.98. Copy the CD onto your computer as well, in either WAV or FLAC format so you won’t lose any quality. Download some free software that will let you play both (more on this later). Connect your computer to your stereo or a good set of headphones, then listen to the two and judge for yourself.

I have lots of high-res audio files, and the difference I notice is usually a little more detail and a more realistic sense of space. Truth be told, these are small differences that require a high-quality audio system or a good set of audiophile headphones to appreciate.

Better Git It in Your System
If you do decide to jump into high-res audio, I’ve got good news: The gear can cost nothing.

The hardware can be as simple as a computer you already own, since most play at least 24/96 audio. The downside is that the audio circuitry built into computers is usually of low quality. But it’s easy to upgrade with an external USB digital-to-analog converter, which connects to your stereo, or with a USB headphone amp, most of which can drive headphones or your stereo.

One of the most popular and affordable USB headphone amps is the AudioQuest DragonFly, which looks like a USB memory stick but incorporates a high-quality USB digital-to-analog converter and a headphone amp. The DragonFly plays audio in resolutions up to 24/96, and at press time the original version was available for $99. You can step up to 24/192 resolution with Meridian’s $299 Explorer.

While the music software most people use, such as iTunes and Windows Media Player, has little or no high-res playback capability, there are plenty of other options, including some free ones. The key thing is that the software has to play the file formats used for high-res audio, usually FLAC or AIFF. If you’re using a PC, try Foobar2000, available as a free download at foobar2000.org. For Mac, try Audirvana, available from audirvana.com in a free version or a $74 step-up version with better fidelity and advanced features.

Extreme High-Res
The recent buzz among high-res enthusiasts is for downloads in Direct Stream Digital, or DSD. Many audiophiles feel DSD has a warmer, more “analog” sound than 24/96 or 24/192 audio. Many software packages, including Audirvana and JRiver, now support it.

Until recently, getting into DSD started at about $1,000 for the hardware. But now it’s dropped to $349, in the form of the Korg DS-DAC-100m USB headphone amp/audio interface. The DS-DAC-100m comes with Korg’s AudioGate 3 software, which plays DSD or standard high-res files up to 24/192.

Some of the effort audiophiles put into going high-res may seem extreme, especially with costs for some high-res gear running well over $10,000. But think of it this way: You’ll be getting as close as any fan probably will to hearing the actual master tapes of your favorite jazz recordings. What’s that worth to you?

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