January 2009

Introducing "The Digital Domain"

My name is Colin Smith, and I haven't played a CD in three years.

In the early 1980s, when digital audio recordings and the personal computer were the next big things, I don’t recall anyone suggesting that these two technologies would one day converge. Audio manufacturers were then concentrating on designing players for the new digital music format, while startups like Microsoft and Apple were far more interested in creating software applications than anything else. Of course, there was also the small problem of getting a CD into a computer. Forget the non-existence of CD-ROM drives; there wasn’t a hard drive in the world that could absorb the data -- 660 megabytes worth -- held on a single CD.

To state the blatantly obvious, times have changed. To ensure that we continue to catch the next big things in audio, SoundStage! is introducing "The Digital Domain," where we will discuss products that lead the way into the new digital-music revolution. The field of potential subjects is so wide open that even we don’t know what will be discussed in these pages as time moves forward. But for starters, allow me to share the journey that led me to computer audio and pass on a few things I’ve learned along the way.

My journey into PC audio (or music servers, whichever you prefer) began about four years ago when I discovered that a device from Hagerman Technology, the HagUSB, had quite a following on an online audio forum. Before I’d found the forum it had never occurred to me to replace my CD player with a computer. The HagUSB and its enthusiastic fans changed my mind. I already had the requisite supporting equipment -- a D/A converter and a laptop -- so I ordered a HagUSB (currently $129) and, while waiting for delivery, I set myself the task of putting my CD collection onto my laptop’s hard drive.

There are many ways to rip (or grab) CDs using popular commercial software like Nero, or the free music players from Microsoft (Windows Media Player), Apple (iTunes), Winamp, J. River and many, many others. After a lot of research, though, I became convinced that none of the above would be good enough to meet my high audiophile standards. However, there was a program that had the stamp of approval from the audiophile masses: Exact Audio Copy (EAC), then and now the gold standard of ripping software.

EAC was written by German audiophile and programmer Andre Weithoff, who introduces his program on the EAC website by saying: "This program is really quite slow in secure mode in comparison with other grabbers, but the program checks every sector over and over to get the correct data with high certainty." In practice, this means that EAC works doggedly to extract every last bit of accurate information from the source disc. It does this, in part, by taking its time with the disc and focusing the computer’s resources on the task at hand. Expect that EAC will take 15 to 20 minutes to read an undamaged CD and verify the data it finds. That’s far slower than iTunes, for example, but that’s the price we pay for being finicky listeners.

Although EAC is widely considered to be the only audiophile CD ripper, it is unfortunately as user friendly as MS-DOS. OK, it’s not that bad, but it does take some time to comprehend EAC’s idiosyncrasies. That doesn’t mean any special skill is required to get EAC ripping bit-perfect copies of your CDs -- EAC’s setup wizard takes all the guesswork out of that. But there are a number of interface and file-naming parameters that will probably need tweaking to meet your personal preferences. For instance, even though I’ve used EAC for years, I still don’t know how to get it to rip tracks in the correct numerical order. At some point I did something to upset EAC (I have no idea what that was) and since then all my rips are in reverse order. I’ve never spent the time to figure out the problem because I use my server as a personal radio station, with my player set on "random" playback to keep everything interesting. That said, my recommendation is to read the many excellent EAC setup tutorials that experienced users have written for the benefit of all before engaging EAC’s services.

There’s a slim possibility that you don’t own any CDs and will exclusively download your music from Internet-based music services. More likely, though, is that you’ll want to expand your collection by downloading new releases and old favorites as they become available online. Unfortunately, not all download services are created equal. Though it’s the most popular by far, Apple's iTunes sells heavily compressed music files that offer bit rates of only 256 kbps (kilobits per second) at most. That’s great if you want 25,000 songs on your iPod and you don’t care about sound quality.

Contrast that miserly bit rate with the 1411 kbps that EAC extracts from 16-bit/44.1kHz CDs. But wait -- there’s more. High-resolution download sites such as that for Linn Records even offer 24/96 files in the Free Lossless Audio Codec (FLAC) format, which churns out 2834 kbps of beautiful music. The implication here is to be aware that a computer, great software and a USB DAC can only do so much with low-resolution files. Remember that old expression: garbage in, garbage out.

Colin's system. From left to right are the Blue Circle USB Thingee, a Western Digital 1TB external drive, a low-end Sony laptop showing Foobar2000, a Synergistic Research Tesla Tricon USB cable, the Benchmark DAC1 Pre and Wadia's 170iTransport. That laptop doesn't normally sit atop the integrated amplifier.

Now we have a hard drive bursting with high-resolution audio files, but we lack playback software. There are quite a number of free playback programs available, and it should be easy to find one that's to your liking. The only caveat with some players is that the lossless file formats that EAC can create (FLAC, for example) won’t play in iTunes or Windows Media Player. For maximum compatibility, I do all my ripping in the uncompressed .WAV format. In my experience these files can be played by all player software, including iTunes. Of course, such files do take up more hard-drive real estate than lossless files (which are more efficiently organized and suffer no known performance penalty), but hard drives are cheap -- a terabyte can be had for around $100 -- so why not go with .WAV?

If you’re interested in trying players that aren’t as visually polished as iTunes for Windows Media Player, Benchmark Media Systems has conducted an extensive look into the pros and cons of a number of playback programs, and though they don’t come right out and say it’s the best ("There are no known problems with regards to Foobar's sonic quality"), I will: I’ve tried every player I have come across, and I always go back to Foobar2000. It’s not as pretty or as funky or as configurable as some, but that’s just fine by me. It seems that Foobar’s programmers put audio performance above all else, and that’s just the way it should be. All that said, I also use iTunes for background listening in conjunction with my iPod Touch’s Remote application. This dandy program, which is free, allows an iPod Touch or iPhone to control iTunes remotely through a home network, turning the handheld device into the coolest audio remote ever. However, when I want to get lost in the music, or when I’m forming opinions for a review, Foobar2000 is my tool of choice.

We now have the ripper and playback software set up, so we must be done. Not by a long shot. In fact, we have to jump right back to the beginning and talk about the operating systems that underlie whichever audio software finds favor with you. Believe it or not, the operating system has a huge effect on the quality of sound that your computer can stream. It would be easy to write a book on the subject, but, briefly, Windows XP forces all audio through an application called the K-Mixer, which distorts the heck out of anything it touches. There is a program, ASIO4ALL, that can supposedly bypass the K-Mixer, but I’ve never had any success using it with a USB converter. Ubuntu, that popular and fun-loving variant of Linux, sounds just awful and should be avoided.

Now, brace yourself for some positive words about Windows Vista. The newest version of Windows has done away with the K-Mixer, and its audio code was rewritten from scratch with high performance in mind. Vista is capable of streaming 24-bit/96kHz high-definition audio files, but even with 16-bit /44.1kHz files (aka Red Book CD) Vista is easily the best-sounding operating system available for the PC platform. Here’s hoping Microsoft doesn’t mess with success in the upcoming Windows 7. In short, if you want to get the best out of your audio server, use Windows Vista. (I plead ignorance when it comes to Apple’s operating system.)

Unfortunately, no one seems to be offering free computer audio hardware, but some of it is so good that its makers certainly deserve to benefit from their hard work. Before going on, I should clarify that a USB converter and a USB DAC are not necessarily the same thing. I use converter to mean a USB device that converts the USB data stream to the S/PDIF output required by most digital-to-analog converters. A USB DAC is a device that first converts the USB signal into S/PDIF or, in some cases, I²S, and then performs the digital-to-analog conversion internally. An example of a USB converter is the HagUSB. An example of a USB DAC is the Benchmark DAC1 USB ($1295). A hybrid of these two would be the Blue Circle USB Thingee, which can output via S/PDIF or use its internal DAC to output line-level analog signals.

The pioneering HagUSB has long since been replaced in my system by a succession of USB audio converters, each of which plugged into a USB port and was recognized by Windows but not always as a USB converter. Even Vista sometimes sees the things as headphones or speakers, but whatever label the operating system imposes there doesn’t seem to be any performance problems associated with its misclassification. Setting up these devices is usually no more complicated than plugging them in and, if you use Foobar2000, selecting the USB converter/DAC as the output device the program should use. This is plug'n'play the way it was meant to be.

Comparing the Benchmark and the Blue Circle units, we can see that each company has taken a very different path in designing its USB products. The Blue Circle Thingee takes its power from the computer’s USB bus, which provides a very low-current 5-volt output. One of the Thingee’s most interesting features is its internal power filter, which does an excellent job of cleaning up the notoriously noisy USB bus supply. By removing that grunge, the Thingee is able to portray music on a very black background. The Benchmark DAC1 USB is what we might call an active USB DAC; it has its own power supply and doesn’t use the power coming through the USB cable. Benchmark has also developed its own proprietary USB interface, which it says makes digital jitter a non-issue. Because the Blue Circle Thingee uses USB-bus power, its analog output is on the low side, meaning the volume has to be turned up when using its analog outputs. The Benchmark DAC1 USB faces no such limitation. There also seems to be no limit to the proliferation of dedicated USB DACs or DACs that have sprouted USB inputs. There are many choices to consider, but for experimental purposes -- and to get a very clear idea of the potential your computer has as a digital source -- it would be very difficult to go wrong with the Blue Circle USB Thingee.

The sum of all these parts is a digital audio source that, based on the reactions of every single person who has heard my system, should be a revelation. Many trends come and go in audio, often because there is little or no substance to them. The audio server is a different animal altogether. The best part is that you’ve got 90% of the equipment you need staring you in the face right now.

So goodbye and farewell, CD. It’s been nice knowing you.

...Colin Smith
colins@soundstage.com