TAS 194: The State of USB Audio
September 6th, 2009 -- by default
Source: The Absolute Sound
Source: The Absolute Sound
For audio software, I loaded my laptop with MediaMonkey, a free program recommended by high-res music sites such as HDTracks. To allow a software comparison, I also installed the less-user-friendly but more sophisticated Foobar 2000. Unfortunately, both of these are Windows-only programs so I was forced to run iTunes on the Mac. I say “forced” because I consider iTunes fatally flawed in that it outputs data at a fixed resolution rather than adopting, on the fly, the sampling rate of the source material. Failing—or simply forgetting—to manually set the proper sample rate for a given track triggers a sonically detrimental rate conversion.
When it came to selecting USB DACs for these sessions, my biggest challenge was narrowing the burgeoning field of candidates. In the end, I chose the Benchmark DAC1 Pre, Bryston’s brand new BDA-1, the equally fresh Audio Research DAC7, and my trusty, Golden Ear Award-winning Resolution Audio Opus 21 stack. (Wavelength Audio, which builds intriguingly innovative USB DACs, unfortunately declined to participate in these tests.) I also spent considerable time evaluating the Bel Canto USB Link 24/96 (a USB-to-S/PDIF converter) and the Focusrite Saffire (a FireWire-to-S/PDIF converter). All of these DACs and converters drove my standard reference system.
Results
Q: First of all, do you really need a USB DAC?
A: In most cases, not really. To understand why, consider the various sources that might drive a DAC. The first category is CD and universal transports. None have USB outputs; all use S/PDIF. The next group is dedicated music servers. Ironically, given that these devices are essentially tailored computers, USB is a rare inclusion while S/PDIF is ubiquitous. How about desktop PCs? They have no need for a USB DAC either. The reason is that these computers are stationary and typically not co-located with the audio system. In order to make contact with the latter, desktop machines rely upon either wired or wireless audio distribution. In such an arrangement, the remote device—not the computer—resides by and connects to the audio system. Once again, among these devices (e.g., Apple’s Airport Express) S/PDIF is the standard output.
That leaves laptops. Here, as previously noted, USB is pervasive. Yet laptops often have another output suitable for music playback. The IEEE 1394 FireWire interface is widespread on products from HP, Dell, Apple, Toshiba, and Sony, and the pro recording industry offers a bevy of boxes that convert FireWire to—you guessed it—S/PDIF. For PCs that lack FireWire, there are now USB-to-S/PDIF converters that likewise obviate the need for a USB interface on the DAC. All of which nets out to this: A USB DAC is necessary only if one’s source is a laptop—and even then, onlyif straight-through USB (i.e., with no converter in the signal path) is the best-sounding option available.
Q: How difficult is it to connect a laptop to a USB DAC?
A: It’s easy. USB DACs are designed for plug-and-play ease of use. Just string a USB cable between the DAC and the PC, then select USB from among the DAC’s input options. When you first make the link, the PC will recognize the DAC as an audio device without so much as the need to load drivers. You will, however, have to tell the operating system that you want your audio funneled to the DAC. This is easily done. On a Mac, go to System Preferences->Sounds->Output. That will bring up all available output devices, at which point you simply select the USB DAC. The procedure is much the same for Windows machines, where the sequence is Control Panel->Sound. In Windows, after selecting the DAC, you will need to click on either “Apply” or “Set Default,” whichever your system presents. Then, and only then, launch your music software (iTunes, MediaMonkey, etc.). You are ready to play music.
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Comments
"Q: How does USB compare to S/PDIF?
A: There is no comparison. USB sounds much worse. All four of the DACs I tested support both USB and S/PDIF, making differentiating the interfaces a cinch. For each DAC, I compared the S/PDIF output of a good CD transport—as well as that of a budget CD player—to the USB output of a laptop, with both sources sending the same bits at the same rate (44.1/16) to the same DAC."
To be fair, this question should have read: "How does USB compare to S/PDIF" using this particular set of devices at this point in time"
IMO, jumping to generalized conclusions based on a small sample of products is like listening to 2 CD randomly selected players and declaring that all CD players sound harsh. There are other USB solutions out there and have been for many years that were not included in this shootout.
Alan! Full Steam Ahead!
How can you be staying the course with a reprint of this article when you have run aground with audio experts on so many fundamental points?
Is bad publicity better than nothing?
Alan,
The problem here is that you did not really prepare for the article. In the first place you are using totally outdated computers. From a background such as yours this just seems silly. Using a sub standard laptop, a totally outdated G series MAC... but here is the kicker... A Win2000 computer. Maybe you didn't read the fine print in the 2000 release notes but Win2000 is not even USB Class 1 compliant. Meaning it does not even support all the functionality required to reproduce audio.
I have had many reviewers use the same laptop Alan is using and said they could not even get 24/96 to operate. I even had one of these sent here and the USB port had error rates so high the output did not classify as MP3 quality.
Next Media Monkey... Alan come on it is a well known fact that Media Monkey is not even bit true.
Gang this is why I withdrew my Cosecant from this review. At the time Alan had never even used a computer for high end audio.
It just seems ashame from a magazine that totes Absolute Sound that they can't even get the basic needs of the computer right for this. Especially in an age were power cords are going for +$800 and he can't even spend that much for a decent computer to do the review with.
It would have been very easy and very appropriate to buy a maxed out Mini for about the same cost as the power cords he is using and merely dual boot the unit into Vista or OSX and have a stable platform and consistent for each operatiing system.
To the editors who I sent many emails before this train wreck occured and numerious afterwards.... I just throw up my hands.... what were you thinking????
Thanks
Gordon Rankin
Not here to plug my own products, just here because I believe in the technology and feel Absolute Sound did a total injustice to it.
Furthermore Taffel and perhaps even TAS have a beef to pick. There is no possibility IMHO, that Alan Taffel could write such an unscientific, biased article unless he was trying to boost sales for the "formerly mainstream" audio hardware manufacturers who support his rag. Have you seen a Wavelength or Ayre ad in TAS recently? No, TAS has refused to have an educated reviewer listen to and comment on asychronous USB Dacs. Notice how the Benchmark products which don't use Gordon Rankin's USB implementation, but are well reviewed nontheless, were panned by Taffel? He couldn't say they sounded good, it would blow the whole article to bits. (As if it could stand on its claims, anyhow). The fact is the newer, USB only DACs sound great. Many DACs that Taffel listened to, with SPDIF and USB inputs, sound poor through the USB inputs because they were placed as an afterthought. The ultimate responsibility here lies with Mr. Harley. This junk article should never have been printed. And to have Steven Stone print an article drooling on about the Music Streamer on the next page is more pathetic. Fact is, get your opinions at Computeraudiophile.com, Stereophile, your local dealer, audiosylum- anywhere but TAS.
Furthermore Taffel and perhaps even TAS have a beef to pick. There is no possibility IMHO, that Alan Taffel could write such an unscientific, biased article unless he was trying to boost sales for the "formerly mainstream" audio hardware manufacturers who support his rag. Have you seen a Wavelength or Ayre ad in TAS recently? No, TAS has refused to have an educated reviewer listen to and comment on asychronous USB Dacs. Notice how the Benchmark products which don't use Gordon Rankin's USB implementation, but are well reviewed nontheless, were panned by Taffel? He couldn't say they sounded good, it would blow the whole article to bits. (As if it could stand on its claims, anyhow). The fact is the newer, USB only DACs sound great. Many DACs that Taffel listened to, with SPDIF and USB inputs, sound poor through the USB inputs because they were placed as an afterthought. The ultimate responsibility here lies with Mr. Harley. This junk article should never have been printed. And to have Steven Stone print an article drooling on about the Music Streamer on the next page is more pathetic. Fact is, get your opinions at Computeraudiophile.com, Stereophile, your local dealer, audiosylum- anywhere but TAS.
I've spoken with several engineers who thoroughly understand USB and there should be nothing in USB, as a physical transport layer, that should affect audio quality. However, because I read this artical and tried a different setup with my system, I now know that for whatever reason, USB does affect quality. I have a PC running XP (in the basement with cable running through the floor so I don't hear the PC's fan and disc seeks) and iTunes. All of my CD are ripped to Apple lossless and I had been playing them via USB to a PS Audio DAC for the past two years. Before I purchased the PS Audio DAC I was using a CardDeluxe sound card. The PS Audio DAC via USB sounded so much better than the analog out of the CardDeluxe I kinda left it at that. I did do an experiment of plugging in a low end CD player (my good CD player was busted) to the DAC via coax, but the PC to USB to DAC sounded much, much better so I left it at that for the past two years. After reading this article I decide to try connecting the PS Audio DAC using a high end coax to the digital out of the CardDeluxe. OMG!! Night and Day. Immense improvement of clarity, soundstage, transients, frequency response...you name it...it all sounds better. Vocals, percussion, strings, everything. Its like I've never heard my CDs before.
I still don't understand why - USB physical layer? Window's USB audio-class driver? or what? But I sure do like it!!!
THANKS FOR WRITING THIS ARTICLE!
I've spoken with several engineers who thoroughly understand USB and there should be nothing in USB, as a physical transport layer, that should affect audio quality. However, because I read this artical and tried a different setup with my system, I now know that for whatever reason, USB does affect quality. I have a PC running XP (in the basement with cable running through the floor so I don't hear the PC's fan and disc seeks) and iTunes. All of my CD are ripped to Apple lossless and I had been playing them via USB to a PS Audio DAC for the past two years. Before I purchased the PS Audio DAC I was using a CardDeluxe sound card. The PS Audio DAC via USB sounded so much better than the analog out of the CardDeluxe I kinda left it at that. I did do an experiment of plugging in a low end CD player (my good CD player was busted) to the DAC via coax, but the PC to USB to DAC sounded much, much better so I left it at that for the past two years. After reading this article I decide to try connecting the PS Audio DAC using a high end coax to the digital out of the CardDeluxe. OMG!! Night and Day. Immense improvement of clarity, soundstage, transients, frequency response...you name it...it all sounds better. Vocals, percussion, strings, everything. Its like I've never heard my CDs before.
I still don't understand why - USB physical layer? Window's USB audio-class driver? or what? But I sure do like it!!!
THANKS FOR WRITING THIS ARTICLE!
Again, in computer to USB audio, quality depends on lots of factors in setup. If you got such a difference with the coax out of your sound card, then you probably needed some software or hardware tweaks to get comparable or better sound from USB. USB done right can sound as good or better than just about any soundcard output (even from COAX). But if you're happy with what you're doing now, that's all that matters for you.
I don't know your "engineer" acquaintances, but I'm willing to bet they have a computer and not a sound background. Computer people will tell you that there is nothing in USB that should affect sound. Audio people with USB experience will tell you that USB can sound great if you know how to use it and set it up for audio.
The problem with the above article is that the reviewer didn't know how to properly use USB for audio, and went on to conclude that "USB can't" give high level results.
I'm an oudiophile that is approaching the world of music on FLAC on hardrives and I'm reading as much as I can to get more info.
Well from all what I read in the previous comments we can assume that if on one hand the quality trhu SPDIF is a no brainer, on the other thru USB, unless the user has a solid foundation in informatic to implement all what it takes to have the USB the perform at it's best, the results are likely to be way below it's true potential and this is a serious issue that makes this technology not very user friendly so far. Is this correct?
It's not that simple. USB takes a little effort to learn the setup, but it's not rocket science.
See http://www.benchmarkmedia.com/wiki/index.php/Computer_Audio_Playback_-_S...
for the basics.
SPDIF is simple, but in many cases unless you have a pro level sound card like a Lynx, won't give sound at the level that properly setup USB will.
USB has some convenience factors in its favor also, once it is setup.
It's not that simple a dichotomy. USB takes a little effort to learn the setup, but it's not rocket science.
See http://www.benchmarkmedia.com/wiki/index.php/Computer_Audio_Playback_-_S...
for the basics - not hard to apply to any server.
SPDIF is simple, but in many cases (unless you have a pro level sound card like a Lynx), won't give sound at the level that properly setup USB will.
USB has some convenience factors in its favor also, once it is setup.