ASUS Xonar U7 7.1 USB Sound Card Review

[AkG]

ASUS’ Xonar U7 has been created in order to capitalize upon the lack of quality audio solutions in many of today’s, small form factor PCs, notebooks, convertible tablets and other mobile devices. With the standard desktop and high end gaming notebook segments already saturated with excellent sound solutions, it was time to once again look at an “outside the box” approach by offering something for those who want better sound quality from the devices they use every day. The Xonar U7 fits that bill by foregoing the add-in card format and using a USB interface to provide a high-end external soundcard.

Most consumers have a love/hate relationship with USB-based external soundcards and DACs. On the one hand there is absolutely no faster, easier way to upgrade the sound playback abilities than to simply plug in an external USB device. On the other side of the coin, by using USB for both data and power the abilities, these devices usually leave a lot to be desired on the audio fidelity front. Mix in a host of problems ranging from poor shielding causing interference to poor drivers leading to compatibility headaches with various applications and the end result has been USB being the black sheep of any soundcard lineup. This is why the $90 Xonar U7 is so interesting; it promises to sidestep most of these issues.

ASUS and their Xonar line of soundcards is certainly no stranger to enthusiasts and over the years these mostly gaming orientated soundcards have garnered numerous accolades from critics and enthusiasts alike. The same however cannot exactly be said about the Xonar 'U' series which have languished in the background, providing portability and iconoclastic looks but less than optimal sound abilities.

So how did ASUS change the tune with their Xonar U7? For starters, it goes far beyond the basic bargain-basement USB DACs that have permeated the portable market. While still relatively portable, the U7 has been built to higher standards with high end internal components and a litany of features. Those components grant a very impressive 114dB SNR with a THD of .0006%, as well as a dedicated headphone amp capable of powering 150ohm headphones. For those keeping track at home, those numbers are actually better than most motherboards’ built-in abilities. The Xonar U7 also has the ability to output a 7.1 signal via either analog or optical connections.

Equally important as the soundcard's hardware features is the software it comes with. In this case, ASUS has provided a lightweight Dolby Home Theatre V4 certified application that’s extremely easy to use and is compatible with Windows / OSX environments. Add in all the usual benefits of USB such as portability, ease of installation, and ease of use and the Xonar U7 has the potential really grab some attention.

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[AkG]

Specifications

Specifications

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[AkG]

A Closer Look at the Xonar U7

A Closer Look at the Xonar U7

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Considering it is part of ASUS' Xonar line of soundcards, the U7 comes in a rather low profile black cardboard container. While it is a touch low key for a Xonar product, the U7's box is still eye catching and filled with information.

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The accessories which accompany the Xonar U7 are rather simple, but that’s to be expected since ASUS was aiming for a plug and play solution which needs just one point of contact between the system and sound card. You get a large installation manual, driver CD, USB 2.0 cable, and an S/PDIF - TOSLINK adapter (which was missing from our sample). Since this model natively supports 7.1 outputs, it doesn’t require a break-out adaptor but we would have still liked to see RCA to 3.5mm adapters to improve upon the native 7.1 abilities.

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The Xonar U7’s hardware is packed into a squat box black with gold accents and is deceptively small considering the number of output options being supported. It measures a mere 1” tall by 3.1” deep by 5.5” long. This firmly places it into the portable category and while too big to fit into a pocket, finding room in the typical carry-on or laptop bag should pose no issues.

On the front panel you will find a dedicated headphone 3.5mm jack, the microphone / line-in jack, and the microphone volume up & down buttons. These buttons simply send proper commands on the system’s OS rather than being hardware volume controllers.

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Atop the device there are three indicator LEDs which glow a pleasing blue. They indicate whether the sound is being sent to the speakers, dedicated headphone output, or the SPDIF port. There’s also a stylish looking volume controller.

Unfortunately this wheel is software-based so it simply sends the proper commands to the OS to raise or lower the volume rather than modifying parameters within the U7 itself. Pressing down on it will also send a mute command to the OS and when pressed a second time will unmute the volume and adjust it back to its original level.

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Around back we see a cramped but functionally well laid out area. There are two (red and white color coded) RCA ports which pull double duty as front channel outputs in 7.1 configurations. Next to them are three 3.5mm outputs (side, center, rear) and the SPDIF port. On the far left side is the USB 2.0 input. All in all these options are impressive given the relatively inexpensive nature of the Xonar U7.

The only potential stumbling points we see here from a features point of view is the lack of RCA adapters (don’t worry, they’re really inexpensive), and that ASUS has decided to go with a USB 2.0 interface rather than use the 3.0 standard. Luckily, RCA adapters aren’t really necessary since most connections for 7.1 will be through the SPDIF optical out port, whereas most headphone users will tap the U7’s dedicated stereo headphone amplifier port.

We understand that USB 2.0 needed to be used in an effort to broaden compatibility with older systems but it does introduce some limitations. For example, the Xonar U7 has access to just 500 miliwatts of power, whereas USB 3.0 would have offered 900mW. ASUS could have used a dual headed USB 2.0 header cable to provide additional power from older setups but decided to avoid the complexity of that route. Hence the U7 is only capable of powering 150ohm headphones compared to its internal Xonar brethren's 600ohm abilities.

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On the underside we can see that along with four small rubber feet is a small switch. This switch changes the Xonar U7 from a USB 2.0 device to the 1.1 standard, providing a much wider compatibility range. Just remember that accidentally switching this to 1.1 can cause problems with newer systems.

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Taking the Xonar U7 apart we can see that the internal PCB has a fairly neat and tidy layout with almost no solder marks. Every trace is clean, which is extremely important for audio quality and consistency. This is a marked difference from may other USB DACs and soundcards we have seen which usually strive to hit a low cost rather than high quality.

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Moving on to the actual internal components, we can see that ASUS has opted for a Cmedia's 6632A as the main controller for the Xonar U7. The USB 2.0 capable 6632 is quite highly regarded and is found in many good USB 2.0 sound cards such as ASUS' Essence 3.

On the DAC side of the equation, the dedicated headphone amp uses a single Cirrus Logic CS4398 IC, while the multi-channel speaker output uses a single Cirrus CS4362. Both are decent if not spectacular choices. Unfortunately, Xonar U7 does not make use of any physical EMI shielding besides separation on the PCB. This is not as big a deal as it is with the U7's internal brethren since it will be outside the PC and thus subjected to a lot less EMI interference.

 

[AkG]

Drivers and Software

Drivers and Software

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The software which accompanies the Xonar U7 reminds us strongly of what’s included with ASUS’ Xonar Phoebus PCIe soundcard. Much like with the Phoebus, this software retains some similarity with the programs accompanying older Xonar models, but it has been streamlined and features an easy-to-navigate interface. Essentially ASUS has combined various applications into one all-encompassing program which is very intuitive to use since it lacks hidden menus. Virtually every setting is never more than a click away.

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The main program consists of one home screen which is broken up into two large columns. The left column is where you can customize the input/output of attached devices with the majority of the information changing based upon the device category that’s been selected. The categories themselves are labeled in clear, easy to understand language, and have large icons which are also surprisingly descriptive.

Also just like the Xonar Phoebus you can’t adjust or customize anything unless the item in question is plugged into the Xonar U7 since the icons will be grayed out. If for example, you wish to adjust your 7.1 speaker output, you will need to first plug in the speakers before being able to access this module. Even the number of volume controls will vary depending on how many jacks are plugged it. The whole thing is really quite intuitive.

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The upside to this layout is you quickly know what’s attached to the U7 and won’t waste time configuring settings which will have no impact on any attached devices. Unfortunately, by making this software self-aware and highly adaptable, advance tweaking is impossible.

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Dolby Digitial features are controlled via their own small software stack aptly labeled Dolby Digital. Much like the main U7 control panel, this application is deceptive “simple” but includes every advanced feature consumers could possibly want. You can easily opt for up-converting stereo output into virtual 5.1 or 7.1, access the integrated ten band equalizer, modify the surround sound effects and even tweak things such as dialog quality.

Taken as a whole, the Dolby Digital program is obviously not meant for advanced users, but it is extremely easy to understand and will be more than sufficient for the vast majority of buyers. More importantly, you don’t have to be an experienced Xonar user to create a sound profile which is tailor-made for your listening profile.

 

[AkG]

Right Mark Audio (RMAA) Testing

Right Mark Audio (RMAA) Testing

Test System Used

Processor: Core i5 2500
Motherboard: Asus P8P67 Deluxe
Memory: 8GB Corsair Vengeance "Blue" DDR3 1600

Graphics card: Asus 5550 passive

While RightMark Audio Analyzer is an extremely good audio test suite, the sheer amount of data and numbers it can produce can be a little on the overwhelming side. To help simplify and make it more easily digestible we have taken what we consider to be the key tests and their results and condensed them into a more easy to understand format.

Harmonic Distortion

This chart is actually made up of two equally important parts “Total Harmonic Distortion” (THD) and “Inter-modulation distortion + Noise Distortion” (IMD + Noise). Too much THD and IMD means your music will be “warm” or “fun” sounding but highly, highly inaccurate. Low THD and a lot of IMD will mean your music is cold sounding AND inaccurate. Low THD and low IMD is what we are looking for as we want as accurate a reproduction as possible and simply choose to either add some “flavor” to the music via the equalizer or simply use different headphones from different companies that colour the music differently.

THD is distortion being added to a given piece of sound. It can take the form of unwanted harmonics, multiples of the original sound, additional unwanted overtones of the original sound or numerous other things being added to the original. While an argument can be made over THD not always being a bad thing (as it can give your music a warmer sound), for serious gaming and audio boards the closer to zero the better.

Noise Level

“Noise Level” is basically the Signal to Noise Ratio a given audio card can produce. The higher or further away from zero a given cards Noise Level is the better. The closer you get to zero the worse the reproduction becomes and the lower the audio fidelity becomes.

To be blunt we were not expecting these results to be as good as they were. Marketing literature that can make even the most mediocre of product seem like it can walk on water, so when reading about the U7 we were taking all the information with a huge grain of salt. Thankfully, there seems to be plenty of truth in ASUS' advertising.

The Xonar U7 may not be up the same standards as the rest of the Xonar line, but it is truly remarkable nonetheless. It really doesn't get any better than this for a USB-based sound card. We doubt many consumers will have the necessary audiophile grade hardware to truly find the limits of this card and that too is rather impressive.

Dynamic Range

Dynamic range is the difference between the quietest and loudest sound a card can produce without distorting them. The greater the Dynamic Range the better.

Once again the synthetic test results are everything we could have ever hoped to see from a consumer grade USB DAC. To say that we are impressed is an understatement as not that long ago this level of performance would have been considered audiophile grade. Of course, those days are long past but we certainly have high hopes for the real world testing stage.

 

[AkG]

Listening Tests: Music and Movies

Listening Tests: Music and Movies

Headphone’s used:
Sennheiser HD595
Sennheiser PC350 (Xense branded)
Psyko Audio Labs 5.1 PC Gaming Headphone

Listening Tests: Music

USB based DAC's that are geared towards the mass market like the Xonar U7 typically exhibit sound reproduction abilities that range from poor to abysmal. Indeed, the bar for this segment is abysmally low.

After the excellent synthetic results we had extremely high hopes for this card and those expectations were easily exceeded. As with internal soundcards, the weakest link will be the source material being used rather than the Xonar U7. While the U7 will introduce some coloration and a certain amount of aberrations, they’re minimal and more than tolerable at everything but the highest volume settings. However, when trying to damage your own ear-drums, the Xonar U7's output quality quickly falls off a veritable cliff but at normal levels the sound fidelity was surprisingly good.

The real secret to this card's success is its headphone amplifier. We would be hesitant to actually use 150ohm headphones with the Xonar U7, but the lack of power that we were afraid of failed to materialize with our Sennheiser HD595’s, proving that USB 2.0 power levels were more than adequate for our use. That’s absolutely a great accomplishment for the U7’s intended market. Hopefully future revisions will make use of USB 3.0 so even higher headphones could be used, but for most people this is simply not going to be an issue.

The same can be said of the soundstage it creates when used with speakers; it may not be the largest or clearest we have ever heard but it is extremely good for USB. We are not fond lovers of up-converted surround sound, but as with the Xonar U7’s overall tonal abilities, we were actually impressed.

Simply put, ASUS’ U7 blows away the abilities of every affordable USB DAC we’ve come across. When paired with a decent analog headset the end results are extremely pleasing. If you’re looking for a good combination of sound and cost, put most of your budget into this device and then spend a more sensible amount on a set of analog headphones rather than buying a USB headset.

The only possible exceptions to this is the possible requirement for wireless communications between a device and the headphones, in which case you will still be stuck with typical wireless USB mediocrity. With that being said, the USB 2.0 cable that the Xonar U7 uses to connect to your system is just a standard one so a longer cable can easily be used if distance becomes an issue.

Listening Tests: Movies

Movies by their very definition are a lot less demanding and require a lot less abilities from a soundcard than other listening habits. However, once again the Xonar U7 shone and did a very, very good job recreating accurate soundstages. The coloration that we first saw in the music testing stage actually helped create a more pleasing movie experience. Dialog was clear and clean, explosions were big without being overly bloomy and overall it was very easy to get immersed into the movie experience.

The only real issue we have with the U7 and movies is the software, which is a touch simplistic. Its lack of advanced features does hinder ASUS’ solution in a minor way. This was especially true when using the software surround sound up-converting alongside movies where the sound engineer didn’t properly mix the background and foreground channels. Without much in the way of modifications, you will be limited to watching and listening to a movie as others intended it to be heard. This is unfortunate, but as with all things software related, it is something that could easily be fixed in the future by ASUS, and we truly hope they do precisely that.

 

[AkG]

Listening Tests: Games

Listening Tests: Games

Games Used:
Aliens vs Predator
BattleField: Bad Company 2
BattleField 4
Borderlands 1 & 2
BioShock 3
Just Cause 2
Call of Duty: Modern Warfare 3
Call of Duty: Ghosts
Tomb Raider
Sleeping Dogs
Metro: Last Light
Assassins Creed: Black Flag

It may not be a 'Republic of Gamers' branded device, but as with most of the Xonar line, the U7 is first and foremost a PC gaming orientated soundcard which simply has music enhancements added on to broaden its appeal. In this regard it is a resounding success. ASUS have spent a lot of time and effort on improving the software capabilities of their Xonar line and the U7 is no exception. When compared to the typical onboard sound solution that ships with most mid-range motherboards, the Xonar U7 is noticeably better. The difference is even more noticeable when it’s lined up against a typical laptop or other portable system.

The only user who won’t be completely impressed is someone who owns an extremely high end motherboard, a gaming notebook with built-in audio enhancements or a dedicated sound card. For example our mITX ASUS Maximus VI Impact has a broader soundstage than the Xonar U7, as do dedicated gaming motherboards like the Gigabyte Z87 G1.Sniper.

Bullets whizzing by overhead, the sound of footsteps creeping up behind the player, and all the other telltales that make a game immersive were present in spades with the U7. Honestly, if we didn’t know a USB based device was being used we would have assumed the sound came from an older generation PCIe add-in card. By the same token, modern day stand alone cards are better than the U7. With that in mind, ASUS’ new external solution has drastically changed out opinion of gaming-oriented USB soundcards

More importantly, this device simply works. In every game we threw at it, the Xonar U7 was recognized and we were instantly able to make use of its unique abilities, sans driver tweaking, registry modding, or anything else that sometimes happens when dealing with USB based audio solutions. Overall this combination of ease of use, and increased performance left us impressed.

 

[AkG]

Conclusion

Conclusion

Going into this review, our expectations were quite low and with good reason. Up until this point, the USB DAC market has been classified by products that provide some audio fidelity uplift but they’ve often been hampered by cost cutting measures that cut down on their benefits. For the most part, even the inexpensive sub-$100 devices have been unable to any semblance of value. Now we have the ASUS Xonar U7, a USB audio solution that has the capability to become an entirely disruptive product. It’s that good.

In nearly every possible way imaginable the Xonar U7 exceeded our wildest expectations. Everything from its impressively low harmonic distortion abilities, to impressive music abilities was top-notch. Even the simulated 7.1 soundstage was a cut above the rest when compared against what passes for competition in its niche. Meanwhile, the dedicated headphone amplifier really boosts audio fidelity when it’s fed with high quality tracks and passed through to compatible headphones.

Another area of strength here is the U7’s ease of use. Due to the necessary drivers, it certainly isn’t plug and play but the included software is designed in a straightforward, welcoming manner and provides enough options that customizing a soundstage becomes quite easy. This is also one of the first external USB audio solutions we’ve come across which didn’t need some form of tweaking to be compatible with every application.

There are a few shortcomings here, many of which can be attributed to the Xonar U7’s impressively low price of just $99. Something had to be sacrificed so you won’t see a user-replaceable op-amp on the headphone amplifier and the software used may be user-friendly but it won’t be up to the expectations of audiophiles. The lack of USB 3.0 capabilities also limits the range of headphones supported by the U7 since it can’t provide the necessary amplifier power to properly feed higher end solutions.

With the U7 ASUS has made wonderful strides in improving their USB-based Xonar offerings. What was once a source of derision in the audiophile community may not become an overnight success with it, but there’s proof here that USB and audio fidelity can walk hand in hand. More importantly, for the average consumer who needs a fast, pain-free, affordable external upgrade to their existing system’s soundcard abilities, the Xonar U7 is hard to beat. It certainly will never replace dedicated PCIe solutions, but for anyone using an SFF or mobile systems this is one of the best options available