Vodoo continued: my final Statement on USB cables

This article here is the final sequel to "Hot Vodoo: Audio differences between USB cables - yes, they do exist" and "More USB cables - more differences". So before you read this one go ahead and scroll through the other two.

Almost one year has passed since my last article concerning USB cables and their sonic signatures was published here. Truth is that I ran out of steam: I didn´t want to do it since I was afraid that I had been measuring the effects of ground loops only. But before I start with the embarassing truth I´ll tell you about the stir those two USB articles created. The articles I refer to (linked above) were written almost a year ago and since then they have been popping up constantly in several online forums. I´ve received visits from Russians, Germans, Americans, Norwegians, Japanese or Chinese citizens to name but a few. Sometimes the participants of these forums made fun of me, sometimes they tried to find out how I was doing things, sometimes I was accused of lying or imagining things and on some occasions people actually tried to help me. It fascinates me to this day that 99 % of all those people didn´t comment here on my blog but only in their respective habitat, forums I´ve never heard of before. Since I´m the most gleefully cunning person I occasionally registered there just to take part in their discussions... and boy, it was delightful to witness how fast participants there transformed from being bullies into polite, elaborate people upon myself unexpectedly taking part in those discussions. Without me it was 'chic' to mock me - so why did people stop when I suddenly entered? I love mockery, especially when it´s about me (I tend to be too self-centered sometimes). This wasn´t restricted to one country, no, it was a trait exhibited by people coming from all around the world. For all those who were doubting me throughout the last year I assume this article will be a field day which is perfectly alright - yet it saddens me that people generally seem to ignore transparency and truthfulness. But let´s start, eh?

USB cables revisited: only the Belkin and the Audioquest were used

In the last article I compared five different USB cables, for the article you are now reading I used only two of them: the Belkin which performed the best & the Audioquest which performed the worst. Since the measurment differences between those two were the strongest I assumed that they´d be the most likely candidates for also showing differences today. Likewise, I used my Creative Labs Soundblaster X-Fi HD USB again... BTW, that was the most peculiar thing... because in those forums I mentionend above I was attacked for measuring cheap hardware 'on my kitchen table'. Well, of course I did, that was the whole point. What good would my test have been if I would measure with expensive boutique hardware (which I don´t own, thank you very much)? I wanted to show results with everyday hardware, something people would actually buy. That way my results would (hopefully) be more comprehensible. Furthermore, assuming that something more expensive is behaving in a superior way is audiophile bullshit. One word about the 'kitchen table' comment... I will ignore it since it reveals opinions much too conservative for my taste. Just something to think about. Back to topic: I had to use the X-Fi HD USB and my ASUS Xonar Essence ST again since I wanted to compare possible differences between one year ago and today. My testing methodology may have changed / improved during the last year, yet I still have to make sure to repeat testing circumstances exactly as before to obtain reliable results.

Creative Labs Soundblaster X-Fi HD USB was used again

For that reason my testing chain then and now consists of the X-Fi HD USB connected via the Audioquest King Cobra RCA cable to the Xonar Essence ST. The last time both soundcards were powered by my desktop PC and since that obviously created the problematic grounding loop I now took a slightly different approach. This time I used my nine year old laptop, an FSC Amilo 1425 which was used to power my X-Fi HD. Naturally this laptop is able to run on batteries, it completely avoids grounding loops that way. Everything else was the same though: the Creative still was connected to the ASUS with exactly the same RCA cable. The laptop uses Windows XP as its OS so I had to utilize the Kernel Streaming plugin for foobar2000 to avoid potentially harmful resampling (one year ago: WASAPI direct connection on Windows 7). Another difference to the older test is that I decided to show you the results of ten test runs (five for every USB cable). I also did five test runs for the last test but I sadly failed to disclose their results. So, let´s have a look at the facts, shall we?

For comparison: Old results, one year ago, both interfaces run from the same PC

Belkin USB cable, two different PCs, one running on batteries,
five different test runs which have been averaged for this table

Audioquest Forest USB cable, two different PCs, one running on batteries,
five different test runs which have been averaged for this table

Shit! You now can see that one year ago I indeed measured the effects of a ground loop caused by using the same PC for both interfaces. With one interface running on batteries and by that removing the ground loop I also removed the measurment differences between the two USB cables, the lower resistance of the Audioquest is not important anymore. Yes, the X-Fi HD USB now measures EXACTLY the same with two different USB cables. Which probably means that 1. differences between USB cables don´t exist or 2. that I indeed can´t measure them with my limited hardware or 3. that I need more and different measurments. In any way, two things are now crystal clear: the X-Fi HD USB is a gorgeous performer on its line-out while the Xonar Essence ST boasts an equally impressive line-in. With measurment results as fantastic as these it´s hard to imagine that more expensive soundcards can do much better; you also have to keep in mind that both cards are relatively cheap and are far away from being hardware for demanding professionals. Just take the noise levels: they have improved by roughly 12 dB - Creative was indeed telling the truth by claiming a noisefloor as low as -114 dB for the X-Fi HD. Back to the USB cables: the only differences I was able to find were so small that they are truly insiginificant:

X-Fi HD USB, Belkin USB cable

X-Fi HD USB, Audioquest Forest USB cable

Click on the upper of those two pictures, that way you can scroll between them using your mouse wheel - only then you´ll see that the X-Fi HD USB has a very, very slightly improved high frequency performance with the Audioquest. That´s it. You could now say "Hey, there is a difference!" Erm... no, there isn´t. It is way too tiny to be of significance. Maybe distortions are able to reveal something else?

X-Fi HD USB, THD & Noise, Belkin USB cable

X-Fi HD USB, THD & Noise, Audioquest USB cable

Again, click on one of those two pictures and scroll between them with your mouse wheel and you´ll see that nothing changes - again. If at all, only the noisefloor seems to reveal a slight tendency in favor of the Belkin so I won´t bore you with additional non-existing differences between two pictures. Today I´ve learned two things: ground loops are evil & USB cable differences cannot be measured when using my approach. Phew, now I´m embarrased: I wrote two articles that were basically describing the effects of a ground loop! Stupid, stupid, stupid. But wait, has the sound changed? That´s where it gets interesting because it hasn´t. The X-Fi HD USB still sounds its best with the Audioquest Forest USB and the worst with the Belkin. Let me point out that the sonic differences are indeed small, I assume that they won´t be audible to 90 % of all people. But I started this article with an emphasis on being honest and truthful (which I always am - and which is painful here) and therefore I´ll tell you that I had doubts about my ability to hear things; I was afraid I might have encountered a prime example of a placebo. So I did what I usually detest, namely a Double Blind Test, the results of which you can see below:

foo_abx 1.3.4 report
foobar2000 v1.2
2013/01/09 02:54:00
File A: RAM-Disk:Audioquest.wav
File B: RAM-Disk:Belkin.wav
02:54:00 : Test started.
02:55:31 : 01/01  50.0%
02:56:05 : 02/02  25.0%
02:56:27 : 03/03  12.5%
02:57:05 : 04/04  6.3%
02:57:18 : 05/05  3.1%
02:57:28 : 05/06  10.9%
02:57:45 : 06/07  6.3%
02:58:01 : 06/08  14.5%
02:58:19 : 07/09  9.0%
02:58:33 : 08/10  5.5%
02:58:48 : 08/11  11.3%
02:58:59 : 09/12  7.3%
02:59:17 : 10/13  4.6%
03:00:01 : 11/14  2.9%
03:00:17 : 12/15  1.8%
03:00:35 : 13/16  1.1%
03:00:51 : 14/17  0.6%
03:00:54 : Test finished.
 ----------
Total: 14/17 (0.6%)

I had occasional problems making out differences. It took me 17 trials during roughly seven minutes to find out if I was imagining things - but now I´m at least confident that my ears (and brain) are still fully functional. I´m no so-called 'Golden Ear', those are a myth. Audiophiles often claim that they are able to hear more than, say, skeptical people relying purely on measurments - which isn´t true. The only thing that´s valid to state is that there are people out there who have trained themselves to hear differently compared to others. I only hear this because I know what to listen for, nothing more. I´m also proud of my (perhaps imaginary) ability of not falling for typical placebo effects. "How can Marlene be so arrogant and full of herself?" you ask... maybe you´re right, look what being conceited brought me: grounding loops! All kidding aside, the situation of most of the time knowing what to listen for really isn´t the easiest thing to live with. I sometimes wish to have the gift of blissful ignorance because everytime I hear an album I immediately spot errors or defects & I cannot enjoy the music until they are gone. This might sound contrived to you but it prompts me to ignore bad sounding albums, even if the music is engaging. Imagine the time I could save by not being obsessed with these things. Enough with the cocky self pitying and back to topic!

Measures extremely well on its line-out: Creative Labs Soundblaster X-Fi HD USB

I´m afraid there isn´t that much to conclude. I still hear the effects of different USB cables, yet I´m unable to measure them; the centuries old dilemma of audiophiles. It all leads to you and the decisions you make, dear reader. Are you a believer or a skeptic? I hate to exploit this common prejudice but I started measuring USB cables through external soundcards as a means of diminishing troubles between those two groups - I thoroughly failed. The only thing I did was creating a lot of hot air. Shame on me. I did however learn a few things: more expensive cables have less resistance causing ground loops to leak through more easily, that I cannot measure everything, that ground loops hamper effective resolution and that the X-Fi HD USB is a great performer on its line-out. But where is the benefit for you?

Hot Voodoo: Audio differences between USB cables - yes, they do exist!

Before you even start I also recommend reading the continuation of this article and also the final conclusion about my USB tests, they are quite interesting and shed an embarrasing light onto the first two.

You might find it ridiculous that I´m talking about sonic differences between USB cables but let me assure that they exist. In theory though - and the audiophile objectivists will tell you that I´m obviously insane, mad or the devil - there shouldn´t be differences at all. I mean, a USB cable is just a digital cable that works inside a computer environment and - unlike an analogue cable affected by magnetism, distortions, noise, etc. - follows a certain set of rules and is unaffected by usual cable defects just like any digital cable. But countless people have claimed that if they connect their USB soundcard to a (usually much) more expensive high-end cable from a boutique manufacturer the sound of this soundcard will be improved considerably. Yes, some of these people are really mad: would you, dear reader, connect a USB soundcard for $ 500 to a USB cable for another $ 500? Yeah, me neither... oh wait, I´m gonna do the same - albeit on a much smaller scale. Gosh, I´m turning into one of those nincompoops full of bigotry ;). And I never was a bigot, I am Marlene Dietrich, an angel, a saint... oh, shut up.

Beautiful, isn´t it? (Copyright by Audioquest)

Anyway, today I´m gonna review or look at an inexpensive USB cable, the Audioquest Forest USB (you can see it above) cable which I bought especially for my SoundBlaster X-Fi USB HD. I´ve owned a special USB cable before which I also bought for my first soundcard, the SoundBlaster Live! 24 Bit external. It was from Monster Cable, looked and felt cheap and was bought in 2004 for little money. The quality of this cable doesn´t seem to be good: after almost eight years in constant use it now starts to disintigrate, the plastic of the plugs looks coloured, the always blinking LED at one end has stopped blinking (which actually is a relief since the blinking was ennerving). That´s when I bought a USB cable from german manufacturer Oehlbach, much better build quality but almost no sonic difference to a standard cable. Then just a few months ago I bought the Impulse USB cable from NuForce and that one finally delivered the audio quality I expected from my external E-MU 0202. Finally a few weeks ago I bought the new Audioquest Forest because I couldnt´find an adapter in order to connect the NuForce Impulse to the Soundblaster (I needed a Micro plug). You can see by that little backstory that I quite believe in different sounding USB cables. Rather unusual as I pride myself in not being prone to audiophile bullshit. Even worse: all those years I have been trusting my ears only - but now with my new and wonderful SoundBlaster and the new cable from Audioquest I finally decided to do some measurments. And here is an important information that I´d like you to read very carefully: when I talk about "measurements" you cannot take that literally! From a scientific standpoint my results are nothing more then nice looking pictures. I don´t know how RMAA "measures" but the pictures you can see most likely are several separate results taken over an unspecified period of time that have been middled or averaged for the picture (in essence, the pictures are all graphs). For showing a real difference I would have to take my five "measurments" of one cable, average them, then take the other cable to do the same. Finally I would have to do a statistically valid comparison or calculation between those two averages to express the differences in percentages. But since I´m not a scientist and since I´m a jerk with statistics I won´t be (cannot) doing this, I´m just Marlene D. and I like to play around a lot.

This is how the cable looks from the inside
according to Audioquest (copyright by Audioquest)

As you can see above the cable uses solid copper conductors, just like every Audioquest cable. I also made very good experiences with my Audioquest Topaz (bought in the '90s) and my King Cobra (the silver connectors are awful though - because silver corrodes) so the decision for a cheap Audioquest cable was easy, it cost 29,- Euros (incl. shipping), half of what my SoundBlaster did cost. Yeah, paying half the money necessary for a brand new SoundBlaster - but for a cable instead.

For this cable to be exact

Overkill, you say? Stupid? Maybe... but I´m gonna show you that my SoundBlaster measures different with this cable and I´m also gonna show you that it sounds different - much different in fact. And just like in my last review I will present to you some excerpts from some tracks I recorded from the SoundBlaster, the first time connected to the standard USB cable, the second time to the Audioquest cable. In case of the SoundBlaster playing back the music I recorded its output with my ASUS Xonar Essence ST (via ASIO with WaveLab), connected with the King Cobra RCA cable of course. On every recording the configuration and the playback / recording levels were exactly the same (on both cards: 0 dBfs) - only the USB cable was different. Samplerates were the same every time, playback was done with WASAPI Event Style on JRiver Media Center when the SoundBlaster was used and with ASIO when the ASUS was used for playback. And just in case: Windows was configured to use the samplerate of 96 kHz only in both cases (as was the ASUS). I even repeated the measurments five times with each cable because I couldn´t believe my eyes: I never expected the SoundBlaster to measure any different when used with different USB cables. But on to the measurments:

IMD, standard cable,
from SoundBlaster to ASUS

IMD, Audioquest cable, from SoundBlaster to ASUS:
the noise floor is much higher and more consistent

Result general performance, standard cable, SoundBlaster to ASUS:
pretty much like my first tests

Result general performance, Audioquest cable, SoundBlaster to ASUS:
much worse. Noisefloor increased for +6 dB, more distortions, more crosstalk.

Surprised? Yeah, me too. I don´t know if the cables is broken. I only know that after seeing those results I tested it with my Sansa Clip+ and an external HDD - no errors or slower speed (because of re-reading faulty data) during data transmission. I assume it has something to do with the power supply unit in my PC, which would explain why these results only show when the SoundBlaster is connected to the ASUS. It´s curious because my power supply is a rather good one from Enermax, a well regarded manufacturer of power supplies. Or it´s my mainboard that is doing something wrong. Or something inside the cable isn´t connected and it´s on the brink of not functioning. I don´t really know, I can only guess. In any case, the SoundBlaster measures worse when connected to the Audioquest cable. Here are now my two ratings for the X-Fi HD USB with the standard cable and the Audioquest:

Standard cable:

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

Audioquest Forest USB

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

For testing I used two scores by Jerry Goldsmith: "Looney Tunes: Back in Action" from 2003 and "Dennis" from 1993. Since you will be able to download those two 30-seconds excerpts from these scores I´m going to explain to what things you have to pay attention to: on the Looney-tunes track there is a percussion group mixed to the front. Behind it you can hear the full orchestra performing. With the Audioquest cable the attacking sforzandos of the orchestra are more noticeable, especially their reverb tails. After one third into the excerpt a plucky synthesizer will join the two groups, mixed to the center area: it can be perceived better with the Audioquest cable. Overall, the sound with the Audioquest has more warmth and more punch - although some people might prefer the more slimmer, seemingly crisper sound when the SoundBlaster is used with its standard cable.

On the Dennis-tracks the virtual stage is not so flat with the Audioquest. Again you can observe a more punchier, warmer sound with an improved perceived dynamic: the deep bass hits of the orchestra are more impressive. With the standard cable the strings sound more like metal, almost gritty. With the Audioquest they have more gloss (which was preferred by J. Goldsmith in the '90s). You should do - as I did - an additional DBT, it too will reveal differences because they simply are big enough to be perceived everytime.

Here are the excerpts - try for yourself

(thanks to MediaFire again for hosting them)

Oh come on, it´s beautiful - for a cable

Which cable do I prefer? I really don´t know. Does the Audioquest fake something? Does the standard cable lie? I´m at a loss here, I cannot answer that question. It appears that I have to continue my testing - I have to get an adapter so that I can use my other USB cables with the SoundBlaster in order to find out if it´s just the Audioquest creating errors/improvements and if the other cables are doing the same - or not. Until then I´m going to enjoy a sound with my SoundBlaster that defies its price of roughly 100,- Euros (incl. the cable) - even if it is not the truth or a somehow faked sound signature.

Latest update: 09.01.2013

Creative Labs Soundblaster X-Fi HD USB / Digital Music Premium HD - is it any good? - A review

Please note that the following review is a major rewrite of the original article where I ended up recommending this soundcard. I cannot do so anymore - to find out why you have to read it again. There´s an alternative for the X-Fi HD USB: the FiiO E07K 'Andes'. It doesn´t feature an RIAA amp and cannot record - but it´s equipped with true 44.1 kHz playback and it sounds just perfect with headphones from 16-150 Ohm.

Since originally posting this article on January 6, 2012 exactly one year has passed and in the meantime I haven´t been inactive when it comes to research concerning the X-Fi HD USB / Digital Music Premium HD. Why would I alter an already written article siginificantly? You know, bloggers consider this to be bad form because it´s not exactly an example of transparency. Secondly it´s unfair to people who might´ve bought this card because of myself recommending it. Point is, during the year that has passed I´ve accumulated some additional information and experience I cannot ignore which will lead me to alter my conclusion considerably. My original conclusion was like this: "...especially for this price - this is a well designed and very good sounding interface with a lot of available connections and features (...) Recording quality is good, playback quality even better, the headphone output is strong enough for most available headphones with impedances from 16-150 Ohms on every system, build quality is well done, design is nice... I cannot wish to have more for the money. Guys, this thing is ridiculously cheap considering its price, it´s a true bargain. I never liked my X-Fi eXtreme Music... but oh, I love this one!" In the end of this now rewritten review you will bear witness to a changed opinion of mine. Yes, I´m ashamed to admit that I seem to have been wrong about many things with this card - I could have gone the easy route and kept my mouth shut. Instead I wanted to be as honest with you as I can be, I would not be able to forgive myself for keeping the truth from you. BTW, this occasion also provided the opportunity to make new and hopefully improved photos. YAY!!

Creative Labs Soundblaster X-Fi HD USB / Digital Music Premium HD

I acquired this little inexpensive gadget only because I´d found out with my then new Sennheiser HD-448 that the headphone output of my Lenovo SL-510 sucks. While this wasn´t obvious with my Superlux it became irritating soon with the very balanced Sennheiser because of missing treble and flat stageing. In the end I decided to buy another soundcard which turned out to be the X-Fi HD USB. True, I could have used my E-MU 0202 USB instead but its headphone output has a high output impedance (22 Ohms) and is pretty weak. Since the new Soundblaster was intended to be used soleley at our second appartement with one of my headphones it was of vital importance for it to contain a strong enough headphone output with low output impedance. For amplifying headphones the card uses the 4556 op-amp by JRC, this amp has been on the market for almost 30 years and it´s still a decent thing considering its price because it has a low output impedance (of just 1 Ohm) in combination with low distortions... that is if it´s treated right. For communication via USB the external card uses the CA0189 from Creative, the high quality D/A-converter is an AK4396VF from Asahi-Kasei while the CS5351 from Cirrus-Logic is responsible for A/D-conversion. But this card has something that distinguishes it from many other USB interfaces: it contains an RIAA amp, enabling you to connect your turntable to this interface directly without the need of an additional pre-amp. I thought that this particular feature might come in handy should I have the desire to capture vinyl. As it turned out during the last year I have not captured one single LP yet (except for testing); it probably has something to do with my strong dislike for this obnoxious and dreaded medium. Well, it doesn´t matter since this feature will not disappear suddenly, won´t it? To my own surprise I have instead used another aspect of this card quite extensively: its digital optical output made it possible to record music onto MiniDisc in high quality.

The inside of the Sound Blaster X-Fi HD USB. Not "audiophile" but high quality.

Copyright by Creative Labs.

I assume that you might have some reservations towards Creative cards; I´m aware that many people experienced problems with them - I myself never did though, every Creative card I´ve owned has been behaving as it should. Manufacturing quality and finish are decent considering the used materials (plastic). It posesses gold-plated connectors (it´s pointless for audio quality; it only avoids corrosion) and its outer shell feels nice to the touch. I especially love how smooth the volume button turns. But it´s very light and that could create problems: imagine plugging in a headphone - the card will simply slip if you don´t hold it in your hand. Setting up the card was easy, installing and upgrading didn´t produce any errors no matter where and on which PC I did it. BTW, I chose not to install the bloated software suite Creative offers, I picked the driver and the audio panel only. Fans of the DSPs typical for Creative (EAX 4.0, THX Studio Pro Crystalizer, Surround etc.) will be happy 'cause the card is equipped with them. Nonetheless they should be aware that all DSP functions are done in software and not in hardware like on the internal X-Fi cards which creates additional computing stress for an older PC or one of those low-power PCs. If you´re willing to experiment a bit, if you want to avoid installing issues or if you´d like to have the newest drivers (Creative is a bit lazy there) I can recommend a fully updated package conceived by the famous Daniel K.; get it here. The DSPs also provide an indication who the target audience for this card is: your average Joe with an interest in good sound quality for every day tasks or gaming, a lot of features and some toys to play around with. Music Professionals? This card lacks routing options, ASIO inputs for multitrack recording or XLR ports so it isn´t suited for professional music production. On the whole it feels like a small gadget able to be connected to your stereo system - that´s actually OK, Creative doesn´t hide this. Several people all around the web have reported that this card can be used as a DAC - I haven´t used it that way yet. Furthermore it still needs a running PC (in order to be powered). Well, it´s nice to have that feature.

Creative Labs Soundblaster X-Fi HD USB front

So far I´ve talked about its relative advantages and the features it offers. What about shortcomings, are there any? Indeed there are! Creative claims that this card offers an audiophile headphone amp. To determine if the JRC 4556 really is of audiophile quality we first have to make clear what the expression 'audiophile' actually means. If it means using anything out of the ordinary then this card isn´t audiophile because it uses readily available, not too costly parts. But as I´ve shown this isn´t an issue because something extremely well sounding can be produced using cheap and simple parts only. Should 'audiophile' mean engineering prowess, then the answer would be Yes/No. Recording and especially playback quality is very decent - but only if you use the line-in / line-out. The headphone output on the other hand seems to be a good example of botched engineering: Creative managed to turn a decent part with perfectly low output impedance into something with an output impedance too high for many headphones the card is actually suited for considering available voltage levels provided by the USB connection. The PCI-Express counterpart for this card, the Titanium HD, uses the same JRC 4556 IC and on that card it has a reported output impedance of 36 Ohms - way too much for IEMs, my HD-448 or my Superlux. I have to make it clear that this isn´t the fault of the IC itself; Creative seems to have added parts to save on engineering and it shows. To find out why that could create problems look at an example from an ancient portable player below:

Sony MZ-R 55 - headphone out with Triple.Fi 10 (copyright not with me)

The frequency reading of this exemplary unit above should ideally be a straight line - instead the high impedance of the MZ-R 55 headphone output creates severe frequency deviations with IEMs which WILL be audible. Since the PCB circuitry for the headphone amplifier looks similar on both Creative cards (according to others) we can safely assume that both will behave in a similar way, meaning that the X-Fi HD USB would have an equally high headphone output impedance creating the same or even stronger deviations like the ones pictured above. Yes, you´d have to say "Bye bye" to balanced sound quality. So in essence with the X-Fi HD USB you´ll have lovely audio quality using its line-out - but the headphone output will produce sonic crap should you be using it with low impedance cans susceptible to high impedance outputs. As a basic rule the headphone impedance should be 8 times higher than the output impedance of the amplifier the headphone is connected to. For the X-Fi HD USB you therefore would need a headphone with an impedance of at least 288 Ohms in order to reach balanced sound. Enter my Sennheiser HD-600 which boasts 300 Ohms... but wait, why is this gorgeous headphone so soft in volume? Because the X-Fi HD USB doesn´t offer enough power for such a demanding and power hungry creature (even though Creative advertises it that way). Which means that for the Creative Labs Soundblaster X-Fi HD USB you´d need a seperate headphone amp to unleash its full potential. Kind of defeats the purpose, don´t you think?

X-Fi HD USB headphone output and microphone input

The disadvantages don´t stop with the dreaded headphone out. Are you planning to play 44.1 / 88.2 kHz material with this card NOT using any resampling? Forget it then. The analogue in-/outputs only offer 48 / 96 kHz sampling rates. This card lacks a seperate crystal needed for 44.1 kHz-based samplerates even though the CA0189 used for USB communication is actually able to handle one of them (44.1). Which creates the second problem: the optical S/PDIF connectors can only process 44.1, 48 & 96 kHz - but they ignore 88.2. Why does all of this pose a problem? Because the good old CD uses a samplerate of 44.1 kHz, a standard the X-Fi HD USB cannot handle with its analogue outputs and inputs. Therefore a CD will always be resampled to 48 kHz or to 96 kHz (depending on what is configured in the Windows WASAPI control panel). Using 88.2 kHz files from for example HDTracks.com with the digital output of this Creative is not possible, at least not without resampling. Digital recording of 88.2 kHz material with its digital input? Don´t even think about it, the card won´t recognize it (I´ve tried). This 'fine' example of engineering seems to have been constructed 15 years ago when those samplerates indeed weren´t very common on PCs. Is this audiophile? I think you can now answer this question yourself.

Backside of the X-Fi HD USB

But now to measurments with RMAA. The first measurment I did for the original review was the commonly employed loopback from the output to the input of the same card via an RCA cable. Many computer magazines do this kind of measurment although it´s unsuitable for finding out if a soundcard behaves well. Using a loopback you for instance don´t know if it´s the output that´s noisy or the input because noise or distortions exhibited by the output are masking the possibly noise- or distortionfree input or vice versa. Therefore I´ve removed it for this updated article. Much more precise than the loopback are seperate testruns done seperately for the line-in and the line-out. So I connected the output of the Soundblaster to the input of the ASUS Xonar Essence ST and the other way round, both times using the same RCA cable. While a PC is inadequate for measuring a soundcard because of grounding issues I knew for certain that my ASUS behaves exceptionally well on it´s in/outputs (noise level of -115 dB for the output and -114 dB for the input, no distortions or jitter). To make it short I was fairly positive that it would be good enough for the purpose of exposing possible flaws of the X-Fi HD USB.

Recording (line in, 50 %): from ASUS to Soundblaster X-Fi HD, one year later,
using two different PCs, one on batteries

Playback (line out, 0 dB fs): from Soundblaster X-Fi HD to ASUS, one year later, 
using two different PCs, one on batteries - spectacular results

My latest article about USB cables made it clear that the playback part of this soundcard is perfectly engineered. During the tests for that article it transpired that I indeed had been measuring the effect of a ground loop a year ago. The result was that the old measurments did not show the possible performance of the Creative so I replaced them with the ones I did for the third article about USB cables. To the measurments: the DAC AK4396V is rated at having a noisefloor of -114 dB (min.) - Creative manages the feet of achieving fantastic -113 dB. Every measurment was done in 24/96 using 0 dB fs for both cards - except on the input of the Sound Blaster: its volume slider produced a perfect 0 dB fs input signal only at 50 % of the available recording level. Setting a recording level of 100 % I experienced severe distortions from an overloading input. That behaviour is caused by the line-in also used as an input for vinyl - the amplifier inside this card is always active. With vinyl records there also is a very noticeable gain of frequencies from 7.000 to 12.000 kHz, beyond those frequencies the band decreases sharply. This indicates capacity problems of the input when receiving vinyl signals but it isn´t a serious issue since 85% of commonly available RIAA amps behave exactly like that. Another thing: either the same line-in/vinyl amplifier of this card is used for the microphone input on the front - or a (possible) seperate microphone amplifier produces noise leaking into the line-in. The latter would demonstrate engineering errors:

Noise, line-in

The left channel is noisier on lower frequencies than the right channel; I assume the left stereo channel of the line-in probably doubles as the monaural microphone input. This is complaining on a high level because this noisefloor is OK for such a low-priced soundinterface. However, a few months ago I´ve stumbled upon an additional row of measurments on another site which revealed strong distortions. Since the loopback method was used I can´t tell if the input or the output distorts, I can only say that I myself haven´t witnessed distortions using the same method. EDIT 05.08.13: Hmm, that blog is now gone. My seperate testruns for recording and playback revealed that they are indeed higher for the input than for the output but non-threatening at all. My unit is practically distortion free though two different units of the same card measuring differently using a loopback might suggest poor quality control on Creatives' side, changed specs or measurments done wrong (happened to me too). Another typical flaw of cheap USB soundcards are high levels of jitter. Not with this card as you can see on the two pictures below:

Jitter, line-in, 24/96

Jitter, line-out, 24/96

The performance is excellent, playback as well as recording are virtually free of jitter. Because I was using a samplerate of 96 kHz for the Creative and 192 kHz for the ASUS I have effectively measured the jitter performance for both cards combined - even more impressive, isn´t it? It wasn´t that surprising since this soundcard employs the asynchronous USB transfer: instead of the PC pushing the data towards it the interface itself demands the data only when needed, it therefore is in complete control of the connection and its data transfer. On earlier USB interfaces the theoretically inferior synchronous or adaptive modes were used, occasionally prompting high jitter levels. I should however mention that asynchronous USB doesn´t automatically guarantees perfect audio, the engineers still need to be skilled to avoid jitter. Are you curious to find out for yourself which USB mode your own USB soundcard uses? In that case I can recommend the USB Decriptor Dumper from Thesycon.

X-Fi HD from above

Before I´ll tell you about audio quality I have to mention that I´ve used the X-Fi HD only in combination with the Audioquest Forest USB cable during the last year. I have written three articles about this and other (supposedly) High End cables: "Hot Vodoo: Audio differences between USB cables - yes, they do exist!" and "More USB cables - more differences", articles that proved to be highly controversial. The third and last article about USB cables "Vodoo continued: my final Statement on USB cables" mainly deals with the effects of a ground loop I have been measuring in the older articles. Also, please note that I´m able to apply my testing methodology only to the line-out but not the headphone output. It goes without saying that I did every single test not using any of the DSPs the card offers.

Sound with the line-out: The sound of this card is very good for playback. Compared to the reference files the Soundblaster X-Fi HD USB lacks a bit of high frequency gloss or 'air' which diminishes resolution and detail a bit. Bass is stronger than my reference files, that difference is small but noticeable. Speed and snap are marvellous over the whole frequency band, music indeed seem a bit 'faster'. Overall, the dynamics are exaggerated; they aren´t completely natural but riveting nonetheless, more importantly they never veer into strident territory. The stage is fascinating too: while it isn´t as wide as the reference it showcases more depth augmenting holographic impression. I found it very pleasing that the X-Fi HD USB borrows some of its characteristics from the excellent Sony D-335. The character of the original files is not retained completely, it´s partly replaced by something with a more forward sound. To put it bluntly: music is more fun coming from this card. In conclusion the line-out is not 100 % sonically invisible but for casual listening (or for almost anyone of its users) it´s perfectly suited. Yes, I think that many people will just love the sound the Creative creates (pun intended). Should you be using the stock USB cable the card was equipped with you will however encounter a flatter stage, its already exaggerated dynamic capabilities will turn from engaging to strident. You decide. Here are now my ratings for the line-out (Audioquest Forest used):

Sonic Balance:

Dynamics:

Resolution:

Stage / Ambiance:

Character:

Recording quality: the frequency deviation with vinyl signals is noticeable, causing hoarse sounding singers and too much 'air'. It´s also responsible for something best described as a brittle sound my two other RIAA amplifiers - which aren´t very good - lack. On the other hand playback of vinyl is not an exact science because of too many factors producing unreliable results. I can only say that for me the quality is good enough (I´d correct errors anyway). Recording usual line-in signals produces a slightly constricted sound, missing resolution and less dynamics. While this doesn´t sound it isn´t because the overall recording quality is decent. The noise signature of the left channel  revealed in my measurments above wasn´t audible.

Sound quality of the headphone output: Despite a way too high output impedance I have yet to encounter imbalanced sound quality with this card using headphones. I seem to have been lucky because my Sennheiser HD-448 and my Superlux HD-668B don´t have any problems with high output impedances, according to measurments on headphone.com they virtually aren´t susceptible to them. Compared to my FiiO E6 this card amplifies lower frequencies, creating more bass power as a result (without sounding bloated). Secondly, it presents music with more dynamics than it really has, making it a bit more aggressive and by that mirroring the sound of the the line-out. Can high impedance headphones like the Sennheiser HD-600 be used with it? Not the best idea, the card doesn´t have enough power for power hungry cans like these, the volume that can be reached might be too soft for some. Using the HD-600 in combination with the maximum volume setting creates distortions on transients; the headphone output cannot deliver what my HD-600 'demands'. Using it with a volume setting slightly below the maximum (90-95 %) these distortions are almost absent, yet the music lacks a bit 'body', meaning soloists have less chest. In short this combination sounds a bit thinner and slightly strident. I have not used IEMs or headphones sensitive to high output impedances with this card and I don´t intend to do so - in such cases I recommend to stay away from this card as far as possible.

Both the HD-448/449 & the HD-668B virtually aren´t susceptible to high output impdances

Concluding my revised article I can only say that the X-Fi HD USB is a mixture of good and bad. Creative claims that this soundcard is for audiophiles. Experience and research however reveal that this claim merely is wishful thinking of Creatives' marketing division and not grounded in reality. Simply put: the headphone output is crap. I´m sorry to say it as blunt as this, even when I consider that I haven´t had any problems at all. But I use headphones not affected by the high output impedance so I´m forced to ignore my own experience in this case. My point is that you, dear reader, probably don´t know if your headphones react to something like this; with this card you might think that the new and nifty cans you just bought don´t sound very well when in reality it is caused by a mismatch between the X-Fi HD USB and your headphone. You plan on using headphones with impedances higher than 250 Ohms to avoid this problem? Congratulations, you´ve just hit another obstacle because this card is too weak to power them sufficiently. Oh, you intend to play CDs in perfect quality with it? I´m sorry but this isn´t possible either because the lack of support for 44.1 kHz based samplerates forces the Windows audio engine to resample using its not very sophisticated interal resampler. You want to play the newest 88.2 kHz remaster of an ancient Rolling Stones album you just bought on HDTracks to feed it digitally to your very well engineered DAC? I´m very sorry, this is impossible too: Windows resampling kicks in again. 
This card is only for you if you can accept a loss in quality - or if you´re using 48 / 96 kHz exclusively, don´t use headphones vulnerable to high output impedance or weak output power and if you plan on correcting frequency errors produced by the RIAA amp needed for vinyl yourself with a high quality EQ. Should you find yourself in the latter description you will get decent manufacturing quality combined with a nifty looking exterior, very decent audio quality on the line-out and tons of DSPs to play with. One thing however is crystal clear: think carefully to which of the two groups you belong for this card is a disappointment in some regards. It took me a year to find out how badly this soundcard performs regarding certain aspects; I subsequently made the decision that this will be my final Creative product. For listening with headphones I can recommend the FiiO E07K 'Andes' warmly, it cannot record, nor does it feature digital in- and outputs, yet it´s impeccably neutral and able to power low impedance headphones competently.

Latest update: 11.01.2013