Furutech GT2 USB Cable (Playback 26)
Making the Most of USB
December 21st, 2009 -- by Chris MartensSource: Playback
OVERVIEW
Consider this USB cable if: you find upper midrange and treble sounds through USB interfaces tend to sound overly bright, edgy, and two-dimensional, and would like a cable that can help address these problems without having a negative impact on low-level sonic details.
Look elsewhere if: you seek a “silver bullet” solution that will magically turn USB into the highest quality digital audio interface there is. Furutech’s GT2 cable improves sound quality in USB applications, but it is not a panacea. Other digital audio interfaces such as S/PDIF may still offer greater performance potential. Nevertheless, the GT2 cable helps USB “be all it can be.”
FEATURES
Furutech’s GT2-series cables provide:
- Furutech’s signature Alpha-process, silver-plated, OCC (Ohno Continuous Cast) high-purity copper conductors.
- What Furutech describes as a “special-grade high-density polyethylene insulation/dielectric.”
- The GT2 cable’s main conductors are surrounded by a three-layer shielding system.
- The cables provide a cable wrap that “includes damping and insulating materials keeping mechanical ringing from affecting the sound.”
- Cable terminations: GT2 cables are terminated with “24k gold-plated USB 2.0 connectors” said to improve grip and to keep “mechanical and electrical distortion at bay.”
Note that Furutech has also developed a sister-line of GT3 cables designed for use in upcoming USB 3.0 applications. The higher specification GT3 cables are designed along similar lines to the GT2 cables, but provide a more elaborate five-layer shielding system.
SONIC CHARACTER
I personally have found that PC-based, USB-driven digital audio systems tend to offer solid, well-resolved bass, clear mids with stable imaging positions, and a good measure of rhythmic drive. The Furutech cable builds upon these core sonic strengths of USB, while contributing clear-cut improvements in two important areas.
First, the GT2 cable attacks the most fundamental problems of USB sound: thin, edgy, and occasionally strident-sounding upper mids and highs. With the GT2 cable in play, these “sins of omission” are mitigated or tempered to a point where the overall sound becomes noticeably smoother and more enjoyable to hear. Even with the GT2 cable in use, one could argue that S/PDIF interfaces still sound better, but the key point is that GT2 cable helps narrow the perceived gap between USB and S/PDIF performance. Forward progress is a good thing.
Interestingly, the GT2 cable does not appear to function as any sort of “filter”—at least not in the sense that it removes unpleasant sonic artifacts, but at the expense of lost musical information. On the contrary, musical information is left intact, while subtle, low-level details seem to be transmitted more effectively than before, which brings me to the second point I want to mention.
With the GT2 cable in play, low-level details, such as subtle ambience or reverberation cues within the music, become easier to hear and more smoothly integrated with the musical whole. Since we are, after all, talking about digital and not analog signals, I cannot explain how or why this happens on a technical level, but it is nevertheless a sonic outcome I have observed. The result is that the system sounds noticeably more nuanced and also more three-dimensional, with more effective rendering of soundstaging cues in the music and a more refined ability to capture the sense of air surrounding instruments and voices.
As I write these comments, I have been doing back and forth listening comparisons between the GT2 cable and a high quality “data grade” USB cable. Perhaps the most obvious difference I’ve observed has nothing to do with tonal balance or frequency response, but everything to do with nuance and subtlety. The data-grade cable gives music a flat, two-dimensional, “color by numbers” quality, while the GT2 cable allows continuous shadings of textures and tonalities to come through more clearly. How it pulls this off remains an unexplained mystery, but I’m glad for the sonic improvements nonetheless.
MUSICAL EXAMPLES
In the “Stepping (Isise)” track from Babatunde Olatunji’s Circle of Drums [Chesky], you’ll hear a wide variety of drums and percussion instruments enfold you, with the ensemble of drums playing complex rolls—panning from stage left to stage right—as one instrument takes up the rhythmic pattern where another leaves off. Occasionally a high cymbal will punctuate a phrase, while the sounds of a high-hat opening and closing will periodically press forward within the ensemble to supply an insistent, rhythmic pulse.
All content, design, and layout are Copyright © 1999 - 2011 NextScreen. All Rights Reserved.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.
Reproduction in whole or part in any form or medium without specific written permission is prohibited.
Comments
This is complete garbage - it's digital cable, NOTHING more.
I would be as rabidly outraged as most here about what seems like obvious nonsense, were it not for my experience with trying a dejitterer device. As someone else here mentioned, if buffering and reclocking are taking place at preamp/receiver end, then it's hard to imagine how any electrical differences can account for any audible difference, because the digital buffer should have the exact same data as the source buffer, in the exact same order, regardless of the connection. However with digital, I think timing of packet arrival, aka jitter, is the key some audible problems, but that can only be so if the digital decoder is basically taking the stream as it gets it. I didn't believe there could be such a difference with the dejitterer claims either, and then I broke down and bought one for about $200 figuring it's a small price to pay, but absolutely expecting to hear no difference at all. To my great surprise, I actually did hear a very noticeable difference. I tried to set up as careful an A/B test as I could, with the caveat of knowing only double-blind, level matched testing would be scientifically valid but impractical for me to acheive. High end, dynamics, and spatial reconstruction all seemed to benefit from my unscientific test. Even my generally non-audiophile partner said he heard the difference. Really, I was nearly dumbfounded. Yet I have to remain skeptical of even my own observations, because I had knowledge of which was which. That's why professional magazines like this one should be obliged to use double-blind comparison as the standard before trying to convince readers to spend 10 times the going rate for supposed high-end cables, which I still think in general are a total racket. I know I've heard one absolutely beautifully cabled system (the guy probably had more money in cables than I have in my whole system) that really didn't sound very good at all to my ears. So based on my dejitterer experience, am I willing to suspend disbelief to try this high end USB cable? Um, no. But if they sent me one, I'd certainly give it a fair shake.
As a newcomer to digital audio, I find some of the comments here a bit disturbing. First, there is a lot of anger from a group that seems to feel that cables can't matter. I have no idea, but the anger suggests to me that they're hiding something. People are outraged that their models of the world might be incomplete? And this from people who don't work professionally in a highly technical field in which engineers struggle to have workable models? Get a grip on reality, folks! My unease is compounded by the nearly universal unwillingness of the angry posters to engage in a dialog. Hmmm....
In contrast, I just read this post from an actual designer in the audio field in the D/A section of the forum, which made me think that the angry people either have an agenda (unrelated to music) or maybe they are confusing computer data processing (non-realtime) with real-time music processing?
"Robert Harley posted this a few days ago, and it deserves to be in this section too:
The current issue of TAS (June/July, Issue 182) includes a letter from reader David Sanford questioning whether slight timing errors in digital-to-analog conversion (jitter) is really audible. The letter was sent in reponse to my review of the Esoteric G-0Rb rubidium clock that improves the timing accuracy of D/A conversion. Mr. Sanford found it hard to believe that a shifting of the sample timing (jitter) by several picoseconds would be audible. In my reply, I mentioned that Keith Johnson once told me he could hear the difference between 8 and 15 picoseconds of jitter. (Keith Johnson is the co-inventor of HDCD, recording engineer of all the Reference Recordings projects, designer for Spectral, and has perhaps the most insightful audio mind of anyone working today.)
Keith read the letter and my reply, and sent me this analysis:
David referred to perception of arrival times of sound and to distortion from jitter in a digital system. These are different things not best compared on a pico-second time scale My comments were about perceptual consequences when timing errors are introduced to digital conversion. Sigma delta methods, particularly one bit, introduce much more destructive artifacts. We hear the consequence of jitter rather than jitter by itself.
The time scale argument is interesting:
We can move forward one loudspeaker of a stereo pair 6 inches – an action creating roughly one half millisecond difference in arrival times to create audible consequence.
When delay or arrival times modulate as fast audio range jitter, one finds reasonable perceptual limits require at least one hundred fold smaller moving displacements. Early magnetic recorders demonstrate this disturbance as their unsupported tape paths were long and produced high-speed irregular motion that imparted a sliding paper character to string instrument sound. Manufacturers introduced idler wheels and loop drives to remove sub micro-inches of this scrape flutter and microseconds of modulation noise. We hear the improved clarity along with reduced coloration in the historic development of phonograph records.
At a million times smaller, pico-second changes to sound paths would pose nano-inch listener and speaker constraints – clearly well beyond reasonable contemplation of audibility.
We tend to think of digital processing as on – off and nothing in between. However, modern sigma delta DACs are configured with analog comparators and filters that operate with an environment of continuously changing voltages or currents. When jitter is introduced to clocks or the internal timing of the DAC is not good, the outputs and decision states from these analog functions become cast in stone before or after the time when responses would have been correct. Now a tally or sampling command produces an artifact or error. The jitter not only propagates as itself to cause some distortion but also produces conversion error and both are memorialized in filters involved with ongoing samples. This compound degradation increases at very high sampling rates a factor where larger performance specification numbers may not always provide better performance. We observe spurious signals, cross modulation, pulse response widening and signal coherent noise modulation – things that have unpleasant names and unpleasant sonic consequence.
I think the example of “audible 8 to 15 pico-second jitter” comes from describing a transport evaluation platform at Spectral. Like many digital playback devices, the fixture has multi-bit sigma delta DACs that require very low jitter to work properly. Hence, we provide direct crystal clocking and other technological supports that one should find in any serious product. We can degrade a synchronization and re-clock circuit intended to isolate optical tracking and servo activity of a CD transport. Then, an RF analyzer shows presence of new jitter related to CD condition and oscilloscope traces reveal moving peaks and spikes riding on clock waveforms. An audio analyzer will display upper band noises as well as widened base lines for continuous sine wave spectra. These artifacts might appear inconsequential except that we must consider the averaging nature of analyzer measurements. We have unsteady nasty waveforms that require experimentation and interpretation to reveal the full damage from the tracking interference. A slight increase of noise is observed and careful manipulation of test signals reveals rapidly changing spurious error in the parts per million – the possibly perceptual category. Similar examination methods reveal peak jitter to be well over 5 times the RMS or specification sheet type values produced from the analyzer. Consequences are audible though more so to others at Spectral than to me.
Keith O. Johnson
Reference Recordings"
To me, this sounds like science -- the willingness to consider and examine hypotheses in search of the truth. Johnson could be wrong, but to my mind he at least suggests that the 'data is data' idea might have some incompleteness.
Here's a discussion from someone who seems to know what they're talking about: http://www.audioasylum.com/forums/pcaudio/messages/7719.html
Basically, it is all ones and zeroes, and you'll only get about one error per month with 16/44.1 audio. The only variable left is jitter (variations in the digital clock). My hunch is that jitter isn't much of a problem, but it might be worth looking into. If you really care, apparently there are a few dacs that use an asynchronous (dac controls the data transfer rate) mode that would totally eliminate jitter.
Now how much the cable affects this, I have no idea. Jitter can be measured with the right equipment. If the cable affects jitter, only a double blind test can determine if this effect is audible. Meanwhile, I'd rather spend my $50 on getting a better dac, or better analogue interconnects (XLR anyone?) than on a pretty USB cable.
Chris -
If you'd written this same article but had thrown in a double-blind test as suggested by Scott and others and come to the same honest conclusion, I guarantee that you'd have garnered far more positive responses than the ones you're seeing here.
That said, I think there are some cases where "bits are NOT bits" regarding digital audio depending upon the transmission protocol in use. The main differences revolve around buffering and error correction, or the lack thereof. I think we can safely argue (to the rational types, that is) that S/PDIF, while digital, is certainly not guaranteed to be "bit perfect"... it does contain CRC data, but it's a one-way protocol that doesn't support re-sending of bad packets if they become corrupt due to timing issues or signal degredation. So I do support the theoretical difference between digital interfaces... but I'd want another double-blind test to prove somebody can hear the difference between any two reasonably functional cables.
While USB in most implementations makes use of error correction (as you'd expect when copying files to/from some sort of external drive or flash device), there are a number of standard streaming audio interface formats for USB audio devices. I'm sure USB DAC manufacturers are free to choose any combination of these features (which may/may not include error correction!), or come up with their own.
http://www.usb.org/developers/devclass_docs/audio10.pdf
There's a somewhat related old discussion of HDMI & error correction here:
http://episteme.arstechnica.com/eve/forums/a/tpc/f/67909965/m/4500058808...
The nutshell is that while the audio & control signals do employ 2-way error correction, the video data itself does NOT. This sorta makese sense to me... minor bit errors will be hard to spot in a large HD image, so this is a trade-off for larger timing & buffering issues that'd come up if you had to re-transmit portions of the signal anytime there was an error.
-Chris B
Chris,
The closest I found to something that can let you perform a checksum analysis is this set of hardware tools:
http://www.beyondlogic.org/usb/protocolanalysers.htm
If you look at the sample output they show there, each frame includes CRC (Cyclic Redundancy Check) data that would tell you if the contents of that frame is intact. That's part of the USB protocol, but I don't know enough about the USB protocol to know if CRC checking can be disabled or if it's a low-level part of the USB protocol itself that cannot be circumvented. This also wouldn't account for jitter, but it would seem to me that sending 1.4 Mbps over a 480 Mbps pipe would pretty much invalidate the jitter argument, since there's plenty of bandwidth there between the sending of each packet to resend it hundreds of times per second, so even if one packet arrived a tiny bit late, the packets are spaced so far apart timewise that it shouldn't create any audible jitter effect.
With regard to your open question about testing different lossless protocols against each other, I have not tried this. I do know that the ripping software I use (Exact Audio Copy) does reference an online checksum database to ensure that the data matches a known-good checksum, but that all happens before compression is introduced into the equation.
-Ivan
that this sort of mush continues to be published. I would like to see if this guy can pick the "good" USB cable in a double-blind study. If not, then maybe it is he who "knows" what isn't so.
I bet he hears differences in power cords, as well.
I believe that Chris believes. Perception always trumps objective reality. We humans have an amazing capacity to create our own subjective reality, and obsessively noodle over infinitessimal differences.
I love electronics, and I love music. I yearn for sonic perfection. But when I start obsessing over the subtle differences between one piece of equipment and another, the music is no longer the focus. The magic is lost.
Electronics are cool. Music can be magic. I'll take music any day. I'll spend my $100 on music.
I applaud the decision to allocate $100 to music.
That said, I think the point of reviews is to help us users avoid having to obsess -- the reviewer has done much of that for us!
I have to also say that I don't read Chris as saying his observations are subjective (the two are confused all the time, but they aren't the same). In fact, he says he thinks you and most other here would hear what he heard -- which is pretty much the definition of objective. In our modern world we often confuse "objective" with "quantified" or "instrumented" but quantification is not necessary for objectivity (e.g. my jeans are blue and pretty much everyone with normally functioning eyes can observe that without quantification or instruments) .
I am listening to a cheap USB cable from a netbook with 192 sample rate from Pandora, through a PS Audio Digital Link III, an Emotiva USP-1 preamp, a Musical Fidelity A3.2cr power amp, KEF XQ30 speakers with IXOS interconnects and Cardas power cords. It sound very good to me now, but with as much as I have invested, it still would be fun to see if I could hear a difference for 100.00. For all of the critics: You just don't get it. It's a hobby. It's fun. Lighten up.
I’m surprised that nobody is drawing the obvious comparison with high-end analog speaker and component cabling. There this same discussion has raged for years, with many folks of scientific bent stating that the differences in impedance and other electrical characteristics of any cabling more substantial and sophisticated than magnet wire can’t possibly have audible characteristics. Proponents of various expensive cables (and magazines in which they advertise) beg to differ.
As in this case, you’d think that properly administered A-B tests would resolve the dispute one way or another. But, nope. In fact, the exotic-cables-are-ineffably-great group has evolved elaborate arguments as to why the very process of double-blind A-B testing is inherently flawed. There are whole message boards devoted to the subject.
No, I don’t buy it personally, but it would be interesting to hear from these guys. Without that perspective, the folks on this thread who say that a straightforward A-B test is the final answer, are simply right. Let’s get it done.
All these "data is data" statements show the same kind of self-assured ignorance we see in birthers. Yes, data is data when it's transferred from one place to another and stored. That's what we see in HDMI cables, where all the data is packetized for transmission, stored at reception, then reassembled.
A conventional DAC doesn't store data. Therefore its performance can be affected by timing errors.
If the USB cable is carrying, say, an MP3 file, then the cable won't matter because it's carrying packetized data. If it's carrying unpacketized digital audio, then the cable can make a difference.
Yep, there's a lot of BS in audio reviews. I haven't tried this cable, and frankly, I scoffed when I read the first paragraph of the review. But after reading the whole thing, I wonder if there might be something to it.
I agree with you, Paul. All these know-it-alls should lighten up. Slamming someone down on the Internet requires neither intelligence nor balls.
I hear you Paul! I invested in a Ceramic floor so that I can hear my self poop in Hi Definition Stereo!
All we need now is a spam bot that speaks incoherent English and says things like "
" Wow! I Learn Much Here now. Interesting Very! You learn much be able now" (Insert stipud link to dead server here)
Tada!
Judging from my own reaction to your article as well as those of the majority of commenters on this page, let's read the results of your double-blind USB cable listening test, as well as some solid technical reasoning behind the conclusions you've drawn in next month's edition. Then, maybe more of us will believe what you have to say on this topic.
I have over 20 years experience in testing RF transmission lines and designing Time Domain Reflectometers for impedance matching, loss, and propagation delay. Here’s my input for what it’s worth.
I do not know how errors in USB cable design might explain perceived or measureable audio quality, but it’s worth mentioning if one wants a quantifiable assessment of USB cables and USB ports.
Can USB cables cause timing errors? Yes – check the usb.org website for the USB 2.0 spec.; section 7.3.2 provides detailed information for signal and cable requirements. From Table 7-8, the high speed frequencies and fast risetimes (minimum 500 ps) used in USB 2.0 are in the area where the signals cannot be considered only digital. Parametric signal and impedance measurements become purely analog.
If the USB cables or the equipment ports are not designed per the specification, then small timing errors and signal reflections (and re-reflections) will be introduced.
1.- Each end of the equipment’s USB ports (master and slave) must meet USB 2.0 specs in terms of signal levels, signal timing, and both termination and source impedance. It is easy for an engineer to design a USB port interface that does not meet the specifications – just don’t read the specs and slap in a circuit that may have long, unbalanced, poorly matched PCB traces (I know, I’ve done it) and wrong values of termination resistors. The USB port will usually work OK, but then, maybe not always if the USB cable doesn’t match the USB port impedance. If one is to perform an audio system evaluation of USB cable, one must first validate and measure the devices USB port parameters.
2.- The physical characteristics of cables and connectors boil down to impedance, velocity of propagation, and signal loss. As to the USB cable itself, these 3 factors are a function of the construction and length of the cable.
The cable must meet section 7.3.2 of the USB 2.0 specification from Table 7-12:
For example high speed differential impedance is 90 ohms +/- 15% ;
and high speed common mode impedance is 30 ohms +/- 30%
Not easy to meet if the vendor is not in control of the cable manufacture process. Impedance errors generate signal reflections which can echo back and forth, resulting in errors in the receiver detection of signal edges.
With a 2 meter USB cable, one-way propagation time will be between 8 and 10 ns depending on the dielectric constant and thickness of the wire insulation. With a cable impedance mismatch to the USB circuits exceeding 30% or so, there could be large echo delays of 16 to 20 ns, possibly creating receiver edge detect delays. I don’t know if edge jitter is recoverable, but it will be there in some situations.
From section 7.3.2 of the USB 2.0 specification from Table 7-12:
One way cable delay is 26 ns max for high speed USB signals
Skew (difference between signal delay on the two wires) is 100 ps, max , meaning the 2 wires must have an electrical length matching better than 1% for a 2 meter cable.
Probably best to stay with 2 meter USB cables for testing and comparisons.
I could go on, but I hope those still paying attention can appreciate potential problems caused by poorly manufactured USB 2.0 cables. I’ve never read any independent lab test reports on quality of USB cables. I guess there’s no money in it. I don’t know if there’s a big problem or no problem, just a bit of information to chew on.
I do like gold plated connector contacts, less prone to corrosion, and it looks nice, too. Maybe not worth big bucks for the high-end cables though.
As an electronics technician who has worked with both microwave test equipment and digital audio, digital data is more than just 1 or 0, on or off. It is also about WHEN one bit ends and another begins, and errors in the time domain in digital are known as jitter. One of the things that can affect jitter is the cable over which the digital signal is sent.
Now, whether this cable can improve sound quality depends on a few things about your DAC. First, does it buffer the data or does it feed directly from the USB receiver to the DAC? If the data is buffered, it is stored and then released in a precisely timed manner reducing the amount of jitter involved. Most DACs are not buffered, making them more sensitive to jitter. Second, does the DAC have it's own clock, or does it generate it's clock from the signal? Master clock is less sensitive to jitter, clock from data signal is more sensitive. Most DACs get their clock from the data signal. Third is the quality of the USB receiver circuit itself. Many DACs use the low rent TI PCM2704 USB receiver chip, which was designed for computer accessory speakers, and has a maximum sample rate of 48KHz. No cable will make this chip sound as good as SPDIF, no matter how much pixie dust is used in it's design.
So, if you have a DAC with a decent receiver circuit, on which can receive high sample rates like 96KHz, or 192KHz, but does not buffer the data before it goes into the DAC, and does not genterate it's own clock, then this cable would probably help minimize jitter, and thus sound better. If not, you would probably see little or no improvement over more pedestrian USB cables. In my own case, my DAC uses the mediocre TI USB chip, so I found that a SPIDF output sound card on my media PC and a good quality SPIDF cabe gave the best results for the least cash.
Thanks Baygul. Let there be light and give that person a medal. We're getting closer to successfully replacing the transport component of the traditional CD player in the audio food chain. Albeit with a far superior user interface and functionality.
So now the big questions;
1. Which reasonably priced DACs in the market today have a decent USB receiver, meaty internal data buffer and their own clock? IE - resolved the jitter issue while still using a $5 USB cable.
2. I stream my digital (AAC) music from iTunes on a PC in another room, across CAT5 through a 100BaseT ethernet hub to an AppleTV, then on to my Pioneer VSX amp via SPDIF. How far am I from being jitter bug free and how can I improve my listening enjoyment further? I would prefer not to a have a PC/Mac humming away amongst my audio gear.
I mean, seriously...this is an early April Fools Joke, yes?
If not, ai yi yi...
First thing: it's the first time I comment on an article seen on the AVguide newsletter, this "article" made me wonder if I've been reading the Fantasy-books newsletter instead by mistake
Second: as an engineer I'm offended you compared us to politicians
Third: believe what you want to believe but do not spread foolish ideas to the unaware!
In the realm of analog signals every kind of black magic is possible and snake oil is sold at every corner. On the digital part instead it's possible to disprove every single piece of "nothingness", like the one present in this "article", with very little equipment and some brain.
Educated people have already suggested how on the comments.
Just to stress one point: if on the source I get "0100011000100..." (it's digital, so it's just zeros and ones, you get the point) and on the other side I can measure the same information, which is terribly simple in digital systems, by definition nothing has changed.
I'm so sad and didn't expect such rubbish from AVguide, a website I came to respect and like a lot.
So dear author, enjoy the $100/$240 cabling lie you're making advertisement of and possibly disappear from the scene of AV "article" writers.
adieu! iva
PS if you really insist on doing this job and have again a perception of "drum rolls sweeping around a wider arc behind your speaker" with new wonderfully advertised cables, I believe it's a signal you changed drugs during the tests. I suggest you to keep using the same pills when changing cables or your honest and professional comparison won't be really fair...
The angry and incredulous comments posted makes makes me wonder whether these guys are 30+ yr old guys living in their mother's basement who listen to mp3 files from their computer using MS Media Player over logitech "audiophile" speakers.
I mean seriously, if digital is digital then digital music should sound the same whether what you use is a $20,000 Audio Aero CDP or a $199 Dell. Clearly to people who seriously listen to music rather than have it as merely background noise, will and can hear a difference between different devices and especially if the device is well designed for music playback. After all isn't that why we read AVGuide (and other audio publication) in the first place to see what is out there so that we may find what may bring us a bit closer to our audio Nirvana?
As for the "science" of why a digital cable WILL make a difference in sound quality, there where a few poster that did offer well written responses, but in summary for the layman, digital music playback happens in real time, data transfer whether it is files, print jobs whatever, are buffered and not real time. This timing difference in music playback is jitter. As I understand it the timing can be forward of backward. It was explained once to me that in a minute there is 60 seconds, but if you vary the length of the seconds in a clock, some faster, some slower, you will still arrive at the average of one minute. This is like the data in music, the bits will all arrive complete but the timing in real time is off and it is audible. The more resolving the system the more audible it is.
Scott, send me an email and I will meet you to do your double blind test. Get your money ready because 10 out of 10 a difference will be heard with a good USB "audio quality" cable, a good reclocker, a good DAC and a good resolving audio system.
Eric
The answer is in Baygul's post. The problem is not the cable, it's the design limitations of the DAC. Once the issues in the DAC are addressed, a $5 USB cable will perform exactly the same as a $500 USB cable.
I do not think the answer is in the design limitation of the DAC. Do you know of an DAC that solved this problem? The answer to the problem lies more with the market dynamics of computers - high volume low cost. As a prior poster said many OEM do not strictly follow standard specification in designing circuits and boards - do they work for standard computing - yes - if it doesn't we can blame MS Windows for bad code :>). Whether a USB cable or even a USB port - mass produced over seas for maximum profit at highest volume for lowest cost and you expect to plug it to your high priced DAC in resolving audiophile system and expect perfect fidelity? Who is smoking the dope? The simple logic would seem to dictate that a specialty cable from a highly reputable audio company who are passionate about audio would make a cable that will produce a sound that is better and different from the USB cable you can pick up for a buck at the dollar store. Even with a good USB cable it is advisable to try the various USB ports as they may sound different as again standards are not strictly followed.A good USB will lessen jitter not eliminate it and thus produce better sounding music period.
Wow, amazing how the replies are much more interesting than the article....and as a result I'll probably continue to check this webzine out, but it continues to verify my thought process on most Reviewers (Chris you may not really be a part of this charade), they're really salesman, period. Sam Tellig of Stereophile is a perfect example, reviews an integrated amp as 'the best he's ever heard!.....so I pick one up used, and it is worse than my vintage Sansui AU-717, so I sell it, and that guy emails me complaining that it's a piece of crap!!!! Go figure....
I have totally had it with bits are bits comments by the Scampolice. I studied EE long before digital electronic was around, but even then my EE professors made comments to my questions about tube circuits that my physics professors just laughed at. I think it is part of being an engineer to accept laws of electronics as absolutes.
At any rate, I have never done a comparison of USB cables, nor heard this one, but I do know many digital designers that consider Firewire much superior to USB (even USB2) and since the bits are bits guys cannot conceive of this being true, I would expect they would dismiss this also. As a result, I reject their arrogant claims as I reject the needs for double blind testing.
What is most amazing about the bits are biters is that they reject the very essence of the science methodology, namely observation. They will not listen using our most refined sense, hearing. Long ago, in the company of many equipment designers, I participated in such a double blind comparison of five preamps, most of which had been designed by the men in the room. We heard each on the same system with the identity of the preamp known only to the man behind the screen and took notes on preamp A, B, etc. Afterwards we rated each. When we compared the rankings, the top unit was not one of these designers. I personally had not ranked the Bozak highest, but did get to take one home to listen in my system. It was awful.
Much later, I participated in the nonsense of same/different 30 hearings. This methodology is embraced by some psychologists but dismissed by others, is also troublesome to me. I could not with any confidence be certain in my answers, but like its critics, I conclude that it is bad methodology.
So, in this case as the many others, I would conclude that we don't use science to make buying decisions, we reflect our tastes. If you bits are biters don't want to listen and keep what you have, certainly do so, but stop this crap about people not being entitled to their tastes, because there can be no differences and justifying this based on man's limited understanding of nature. My position undercuts the position of the reviewer, of course. He is merely expressing his tastes. Sam Tellig's supposed response above, is just arrogance. If your tastes go along with those of a reviewer, pay attention to his reviews.
Old&bored: interesting perspective. Thanks. It would be interesting to hear more of the detail of the experiments you mention.
I would only add that observation and taste don't have to be the same thing. You and I can both observe that the girl next to us at the bar is slender. We may not agree on whether we like that (taste). Reviewers can, in principle, observe without imposing their taste. By blurring the words (which is done all the time by those who call observation "subjective") we can lose a lot of meaning. Imagine if people used "voltage" and "current" interchangeably! Now it might be that Chris is expressing his tastes, but that's not how I read much of the original review.
You know, If God has to make MKII bible (the new testament) then certainly, we can all understand that being a Pundit is not easy. Cable reviews are always going to be hard to do. There is only so much you can really investigate. That is why they put the girly boys in the Music Review department and auditioning loudspeakers. (You hear that Robert Hartley! :-)
I would hate to do my hobby as a job. Everyone can agree on this. You got to pay the bills. Give the guy some slack. Canceling a subscription over this is kind of like getting pissed off that there are no real black people that work at Popeye's chicken.
And Ronald McDonald is a Vegan!.
Remember kids, Facts, like life, Are what YOU make them. Cheeseburgers don't need warning labels. But for some reason, you need one on a pack of Camels?
Go Figure...
Why bother with Cables at all! Lets just go Wireless! I can't wait till they start selling Air in a can! LOL! Or tell you to move to places with less stuff in the air so that the signal is more pure! And life like!
The lulz here is that we are dealing with USB. Not Firewire. Not SDDI. Universal Serial Bus. USB can not even operate without the CPU. (many will not get this) Firewire is able to work independently of the CPU. Has more bandwidth (even at 400Mbps) then USB. And is MADE FROM THE GROUND UP FOR THIS KIND OF WORK!
Cheap USB cables just work. It was made that way. There is allot of room for improvement in USB. (or at least Insurance) Why even bother with second best? Firewire is there. Has some of the best cables. Is stringently controlled. And has the High cost that people need to justify there lives.
Good Cables start around $50. (they can be had for less, but why chance it!) And Make your own Data grade ones over the new Cat7 cables!) It is in the standard!
Going for convenience over substance has always been a bad idea. USB 3.0 has some promise, to make Firewire obsolete.
It's like having a $1500 dollar DAC that only does MP3 audio. Sure it makes them sound good. Has tubes. And makes the compressed lossy music better in every way even aesthetically. . But it is still an mp3 file coming out when you could of had Redbook, even raw 24/192 !
The cable is not the issue. You have a choice. Use that Choice before it is gone. Besides. Tell me of just one gold plated, Poly cap, Silver trace, USB card! (there were Firewire cards made to these specifications for Audio and Video transmission in the past, but the pros never could tell the difference and neither could Texas Instruments or the military in their use of it in a fighter jet ,)
No mater what. It's like the cassette Vs. the CD. No matter what. The CD is just better then Cassette tape. Not better then tape mind you, just 3.5ips tape.
So instead of making DAC tapes, You just throw it away and start with a clean CD and work on it from there. Folks using USB are the same people that liked using tape and pushed tape to where it was. It was a Fun convenient format. Just like USB. Nothing wrong with pushing the envelope. And there are benefits to pushing the envelope indeed.
USB dacs are like tape decks. They can be really good. And be as good with the proper precautions are taken into effect as Firewire.
But why?
The next holy grail is HDMI. (But if you are me, The fact that they keep having to release firmware upgrades to deal with the audio portion scares me. ) HDMI Has never sounded right with (SACD) music to me, But does a great job with Dolby and DTS tracks
But if you are using a computer for audio. The finding that the iPod sounds better then a Normal PC can and should not surprise you. The(old) IPod has dedicated electronics for that very purpose. The PC has allot of overhead to do the same thing. when you look at a source first approach. There is so much wrong here it just boggles the mind.
Taking the weakest link approach, makes more sense here. But what is the weakest link? And how can you know? That is what this Review is just missing. I doubt that the reviewer has time to really go into this. Computer audio is a Beast! And it is in its Infancy. That fact is never given out! Cables even for digital audio can and do matter.
I don;t doubt what the reviewer heard. I hear voices all the time and see things!
But people with imaginary friends need to understand that there is no understanding for taste. And leave it to that. It is again a hobby. Just like religion or "WOrds of God" .
If I wanted facts. I'd make up my own :-)
Pure, utter, complete, nonsense, for people who feel the need to believe in "wire" as something you can hear.
If cables were just cables. Well then Why cant I get CD quality audio over my telephone cables? Might be realted to bandwidth? You can hear cable. (Hello, Crossovers!) But I agree, there is a certain lunacy limit. After that. well, it's just an umbrealla policy after that. But The price of these cables are like 60 bucks. Witch really aint that bad. Norstroum underwear can go for 6 bucks each for a toddler. SO $36. for a weeks worth of ball holding. At $60, This cable is well priced for a boutique style market. And it's not as bad as paying $1,500 for a USB cable.
Although I am not a fan of PVC and the static build up. This cable might be made to take advantage of that. Oh well.
"There are more fools than knaves in the world, else
the knaves would not have enough to live upon."
- Samuel Butler, digital audio pioneer (1612-1680)
I do not want to argue with anyone. This post is for the reviewer and for any person out there that does not have a firm, almost religious, opinion on either side of this discussion.
I am a stingy audiophile wannabe. I want to think that with very little spent I can produce quality sound reproduction on par with gazillion dollar systems. Stingy as I am, I would love to believe that bits are bits. Being an engineer, I would love to rationalize the bits are bits argument and save myself not $100 but $500 or even $1000USD. Yes there are USB cables that run for $1000.
I have not tried the specific cables here reviewed. So my comments are based on my specific system with the few cables available to me:
Setup 1: Vista PC – OffRamp 3 Ultraclock
Setup 2: MAC MINI - OffRamp 3 Ultraclock
Cables used, several high quality computer USB cables and AXIS USB cable.
The differences are not by any means subtle. No side by side tests required. The order of magnitude in sound performance is on par with a high end DAC upgrade. Period. End of argument.
There are several high quality USB converters that claim to be less sensitive to the cables used in their setup. Sync. vs Async. Technologies, USB vs FireWire interfaces etc. and it may be so. However, using either the OffRamp3 or the HAGUSB, the cable used made as much of an improvement as could be expected when upgrading to a high end DAC. Hey, I paid quite a bit for my cable and was criticized by all my hobby pals who also claim to be stingy audiophile wannabes. After they tried the USB cable, they ALL, yes ALL, ordered one for their systems (which by the way they are all very similar to mine).
First, I would like to congratulate the reviewer for standing by his review. Second, I want to encourage any one that is not religiously sold on either side of this argument to try some of the alternatives the reviewer suggests to verify that bits are not always bits. I know I tried most of the recommendations posted by the reviewer before even considering forking more than a few dollars for a USB cable. Heck, try changing the USB output port on your computer and see if you hear a difference. Some people claim that on a given computer, different usb ports have different sounds. I have not been able to notice these differences on my system but some claim that there are differences to be heard by just changing the USB port used. In any case, I do not want to detract from the fact that a USB cable made an improvement in my system comparable to a high quality DAC upgrade. This is really nothing at all like looking for differences on independent USB ports.
For background, I'm an MSME who spent most of his career in software, culminating in 6 years as CTO of a F500 software company. I'm hardly a credulous subjectivist, either by training or by temperament. But a lot of the righteous certainty expressed (often hyperbolically) by the "objectivists" on this thread is just plain fundamentalist ignorance.
The criticisms of the review fall into two camps: 1). You can't possibly have heard any differences, because it's impossible for cables to change the sound, and/or 2). the only valid way to determine audible differences is a double blind test (DBT).
Let's look at each of these in turn. First, as a number of posters have already pointed out, the USB audio protocol used by most DACs today is a synchronous protocol, very different from the packet-based protocols used to transmit data between a CPU and other types of peripherals. Synchronous digital transmission protocols, like SPDIF, AES, and synchronous USB, are transmitting both data and clock (timing) in the same analog signal. Accurately recovering the data is trivially simple compared with accurately recovering the timing. That is significant.
All digital audio systems exhibit some degree of timing error (aka jitter), which only becomes significant when the signal is transformed back to analog. Errors in timing of the data stream fed to the reconstruction filter(s) create distortion in the analog output. This distortion is enharmonic, and thus audible at much lower magnitudes than the harmonic distortion introduced by analog components and speakers. The magnitude of jitter-related distortion depends in a complex way on the characteristics of the jitter itself, as well as the encoded audio signal. None of this is controversial or unscientific; digital transmission jitter has been studied extensively, in both audio and other contexts.
Can cables impact jitter? Yes, in fact from the perspective of pure physics, it's impossible for a cable not to impact timing in a synchronous digital transmission system, because the signal itself is effectively "analog". How much those timing errors will impact the final analog signal depends in a very complex way on interactions between the cables, the transmitting and receiving circuits, the signal data itself, and the type and implementation of various clock recovery (de-jittering) schemes on the receiving end, but in general it is not possible to make a cable which will be perfectly "transparent" in the context of a complete system. So, in an absolute sense, the question of whether USB or SPDIF cables can impact the sound is pretty simple: of course they can. In fact, they almost must.
(BTW, for an object lesson in the dangers of oversimplifying systemic interactions between components, see the following set of measurements on speaker cables: http://www.audiodesignline.com/howto/showArticle.jhtml?articleID=201807390 in which the experimenters were shocked, shocked to find out that cables and amplifiers behave unexpectedly non-linearly when connected to a real load instead of a resistor).
OK, so yes, there can be differences in the analog audio signal resulting from "digital" cables. Are those differences audible? Well, that question can't be answered in general, because it's so dependent on both the specific system, and the listener. Here's where we get to that DBT part.
There is nothing wrong with applying DBT testing, per se, to audio equipment, just as long as we keep in mind what it is we are testing. Specifically, DBT testing as applied to audio conflates four different tests into one test. If a double blind test does not yield a statistically significant difference, at least these possibilities exist: 1). there are no differences in the physical sound between A and B, or 2). the differences in sound between A and B fall below the perceptual threshold of the test subject's hearing mechanism, or 3). A and B sound different at a level which could rise above the perceptual threshold, but the differences are too obscured by the rest of the test environment, or 4). the differences between A and B rise above the perceptual threshold, but are not sufficiently recognized or remembered to enable the test subject to reliably identify the source.
It is this fourth factor - the impact of cognition on the outcome - which makes DBT as applied to audio quite different from DBT as applied to, say, drug testing. It is often observed in audio DBT, in cases where subtle differences are uncontroversially acknowledged to be present (such as tests of lossy audio codecs), that "experienced" listeners are more statistically likely to identify differences. It's possible that experienced listeners are experienced because they can hear better, but given the disproportionately high representation of older males in the audiophile community, that seems unlikely. Experienced listeners just know what to listen for. When you think about it, this is not surprising. If we do a DBT on two different Stradivarius violins, who is more likely to reliably distinguish them? An untrained listener off the street, or the person who has owned and played one of the two Strads for the last 20 years? Any listening test - blind or not - is testing sound, hearing, and cognition, and is subject to deficiencies in any of these. There is no way to construct a music listening test which conclusively proves what can and cannot be heard, because hearing can't be isolated as an independent variable.
A further observation about the limits of audio DBTs falls out of this discussion. In a double blind test of, say, drugs, we not only assume that cognition (outside of the placebo effect) does not impact the results, but we also ignore statistical "flyers". If one test subject gets spectacularly better while taking the test drug, but nobody else does, the drug has failed. We chalk up the flyer to some combination of factors not applicable to the general population. But here's the thing: audiophiles are "flyers" by definition. The differences between the two Stradivari are of no import to the general populace, but Itzhak Perlman is a different story. The ability to detect woodwind sound reflecting off the orchestral shell is of no import to the general population, but it is to me. Most audio DBTs are simply not oriented toward detecting the kinds of subtle differences interesting to audiophiles.
Yes, single blind listening is obviously subject to serious errors such as confirmation bias, and attempting to confirm results through other mechanisms such as measurements and double blind tests is something "subjectivist" magazines should do much more often. At the same time, I'll submit that many advances in audio reproduction were introduced by engineers who used their ears as their primary tool. I remember well the controversies surrounding digital audio in the early days, 30 years ago. Objectivists, using the measurements they'd used to evaluate the analog world, found that digital audio measured essentially "perfect", and their ears confirmed what their measurements told them. Professionals who cared mostly about sound, however, like many recording engineers, insisted that these early digital recordings didn't sound "right" at all. And sure enough, over time, the causes of various digital audio artifacts became studied and understood, measurements were devised, listening tests which exaggerated the phenomena educated audio professionals on how to hear these things, and a whole host of technical improvements ranging from dither and noise shaping to jitter reduction to anti-aliasing and reconstruction filter design, among many others, were employed to attack and reduced the unique problems of digital audio. What is especially ironic is that some of those types who proclaimed digital "perfect" way back then (hello, Brad Meyer) now take the line that, of course, those early systems had issues but we've fixed all of them now! I reserve the right to be skeptical.
A few conclusions:
- Don't be too quick to think you understand everything significant about the role of any part of an audio system. The fundamental scientific attitude is curious and appropriately skeptical, not judgmental.
- Claims of audible differences in components must also be subjected to both curiosity and skepticism. Could there really be a phenomenon creating an audible difference? Think creatively - what could that phenomenon be, how would we identify and measure it? Is that phenomenon significant enough to be audible?
- Remember what Bob Stuart of Meridian, digital audio pioneer, degreed as both an audio engineer and psycho acoustician, says: we don't yet know enough about how we hear and listen to rely solely on measurements.
- Don't rush to judgment and post vitriolic nonsense accusing other people of credulous idiocy. It's unseemly, and very unscientific.
Bravo ScottB. That was logical & inspiring! Enough to inspire me to go out and listen to various USB cables to see if I could hear a difference. And there IS audible difference. Very clearly for I and several of my colleagues. (Interestingly the most expensive cable wasn't necessarily the best sounding one.) Thanks for some logical sanity in this thread. Hope the close minded fools in the bit-is-bit camp are also inspired to LISTEN to various setups. I should know, I used to be one of them!
I have tried two usb cables from Kimber Kable. My first cable ($70.00) seemed to filter some noise at the expense of reduced dynamics. The KK Silver (AG) @ $140.00 not only reduced dynamics but smeared the music so much that I removed it from my system. It was in service for 3 months before the smearing took place. Now using original usb cable that came with my Benchmark HDR. My experience with USB cables has proven to me, that the theoretical designs of digital USB cables does not match the actual performance characteristics that its designers say they have achieved. The $210.00 spent was a waste of hard earned cash.
I have tried two usb cables from Kimber Kable. My first cable ($70.00) seemed to filter some noise at the expense of reduced dynamics. The KK Silver (AG) @ $140.00 not only reduced dynamics but smeared the music so much that I removed it from my system. It was in service for 3 months before the smearing took place. Now using original usb cable that came with my Benchmark HDR. My experience with USB cables has proven to me, that the theoretical designs of digital USB cables does not match the actual performance characteristics that its designers say they have achieved. The $210.00 spent was a waste of hard earned cash.
This is the type of nonsense that costs cunsumers millions of dollars for nothing each year. Here is a claim that has NO basis in fact, yet, the writer attacks the "real engineers". Well, as a real engineer, I have equipment that can measure such claims. If it can't be measured, how can a manufacturer test their own design?
You keep on listening, that's what you do best.
We still don't know enough about how humans hear, what they can hear, and how it affects perception of music. You can't "measure such claims" because you don't even know what to measure.
Example: In the 80's, engineers "measured" digital reproduction and said it was perfect. Musicians and audio professionals claimed it wasn't. The only problem wa that the engineers didn't know what to measure, as they were still thinking in terms of the measurements they had done for traditional analogue transmission.
We now know that jitter exists in digital reproduction, and that humans are very sensitive to it. Some anecdotal data suggests that humans with trained ears can distinguish jitter on a level of under 10 picoseconds. This also was thought to be impossible only recently.
That's just one example, there are others. And 10 years from now we will know of other factors which we aren't even taking into account today.
I started reading this USB cable review and I was chuckling to myself because I was so sure it was a really clever spoof. Then I realised that the reviewer was actually serious. That's almost more amusing. There's one word for this kind of gear, taken from the equally crazy pharmaceutical industry, and that's 'placebo'. Yes, anyone who claims that a digital connection can be influenced in some auditory fashion (barring out and out signal drop-outs) by the quality or otherwise of a cable is suffering from the placebo effect. In the drug industry, they sell named brand paracetamol for more than 10x the price of generics, and do you know what - they do exactly the same thing! However, there's this interesting placebo effect where named brand drugs are shown to work better because the people buying them believe they must be better because they cost more, even though the only difference between them is the packaging. Fascinating stuff. It's clear that the guy writing this article doesn't have the faintest idea about digital system design. Anything digital which relies on a data feed from another component arriving at a given rate is going to have an in-built buffer to eliminate the kind of 'jitter' or delay in the data stream transport. If it doesn't, you need to buy some better digital equipment, as the device you have is obviously very poorly engineered. If your cable is so bad that you find the buffer becoming depleted, you're not going to get a 'slight change' in the way it sounds (richer, harsher etc.) you're going to get something totally distorted. Digital drop-outs don't happen in the nice, gradual way you get with analogue signal loss - they are extreme and catastrophic. Anyone experiencing them will be able to recognise it - audiophile or not. I have to say that another parallel which occurs to me reading this thread is a debate between atheists and religions people. "Have faith" say the religious - but those pesky old atheists keep pointing out the Emperor's got no clothes on and they don't like it, do they?