ASUS Xonar Essence ST/STX soundcards Page 2

ASUS recommends that, using the Windows Control Panel, you first disable any existing audio hardware before you install the Essence's supplied drivers. Installing the drivers also installs the Xonar Audio Center program, which allows you to adjust the card's settings. Here I ran into a problem: playing a 96 or 192kHz file with either Foobar 2000 (v. or Adobe Audition 3.0 and setting the appropriate sample rate with Audio Center didn't give a sound from the STX card that was noticeably better than standard CD-sourced files. I played some test tones, and it appeared that even when the sample rate was set correctly—confirmed both by selecting the digital output and by checking the sample-rate display on the dCS Puccini D/A processor to which it was attached, and by looking at the STX's properties in the Vista Control Panel's Audio Devices window—96 and 192kHz files were being downsampled to 48kHz, with spectral components higher than 24kHz aliased into the audioband (eg, a 40kHz tone was reproduced as 8kHz). I reinstalled the driver and the software, but to no avail. (This didn't happen with the ST version of the Essence installed in the older PC running Windows XP.)

The fix was to download and install ASIO4.DLL (see this guide to setting up Windows for audio playback), then select that as the default sound device in Foobar's Playback Preferences dialog. I let ASUS's technical support know about the problem, but by press time they still had not gotten back to me. But it concerned me that if there was an incompatibility between my PC, Vista, the Xonar software, and the jukebox software, there was no immediate way of knowing something was wrong, as music still played. Windows 7 was released as this issue went to press, so I will install the new operating system on the Shuttle PC, along with the appropriate ASUS driver, and report in a Follow-Up if this resolves any potential sample-rate problem.

The other issue that raised its head during setup was not a problem as such, but the fact that the STX and ST can't play files with 88.2 or 176.4kHz sample rates in a bit-transparent manner, which they will do with 96 and 192kHz data. The cards will indeed play 88.2 and 176.4 files, but will convert their sample rate on the fly to whatever rate has been set with the Xonar Audio Center. ASUS claims that the Essence cards' built-in sample-rate converter is of very high quality, but there will still be a loss of ultimate sound quality with 88.2 and 176.4kHz files.

I copied my iTunes library, which I usually use with my Apple G4 Mac mini, to an external USB drive, which I could use with both the ST and STX computers. Almost all of my auditioning was performed with the STX card, however. Files were played back with Foobar and ASIO4. One boon of this setup was that a helper app enables Foobar to play Apple Lossless files, allowing me to use my iTunes library without having to first transcode the files to FLAC or the uncompressed AIF or WAV formats. Another was that another helper app allows Foobar to play DVD-Audio discs in the PC's drive. (The tracks are helpfully identified as being multichannel or two-channel.) I didn't try any of the Essence's DSP effects—I used the card only as a straight, high-quality digital source.

Setting Foobar to Shuffle with CD-sourced files while I sat at the desk in my listening room to edit magazine copy, it was apparent that the Xonar Essence's analog outputs offered serious sound quality. The DVD-A of Neil Young's Harvest (Reprise 48100-9) drew me into the music, and the blend of James Taylor's and Linda's Ronstadt's voices behind Young on "Heart of Gold" was well delineated without obscuring the individuality of their sounds.

Returning to the listening chair, low frequencies had suitable impact and weight, the midrange was uncolored, with excellent clarity, and the high frequencies sounded very clean, with good air around sound sources. In Joni Mitchell's "On France They Kiss on Main Street" (from Shadows and Light, Asylum 704-2), the cymbals had an excellent combination of sheen and sizzle without the latter being unnaturally emphasized—although, of course, the HDCD decoding was not being applied. And on "The Dry Cleaner from Des Moines," Jaco Pastorius's display of walking-bass virtuosity on fretless Fender was reproduced with authority, as was Don Alias's kick drum: The balance between the "pat" of the initial drum-head transient and the "purr" of the subsequent body tone was well managed.

The same was true for a 24/96 piano recording I made at the beginning of November for a live vs recorded demonstration organized by Philip O'Hanlon of Luxman and Vivid distributor On a Higher Note. I had to record a little closer/drier than was optimal, so that the double hit of the same acoustic was not too disturbing on playback. But the Xonar Essence did a great job of conveying the full weight of the Steinway D as pianist Genadi Zagor pounded its left-hand keys at the climax of Mussorgsky's Pictures at an Exhibition. (If you're going to be at the Consumer Electronics Show this month, O'Hanlon will be playing this recording in his suite.)

ASUSTeK Computer Inc.
US distributor: ASUS Computer International
44370 Nobel Drive
Fremont, CA 94538
(812) 282-2787

Xavier Xerxes's picture


Thanks for your review.  I would like to use the digital and analog output connections at the same time: digital for my home theater 5.1 experience and the analog to be connected to a 12-zone amplifier.


Is it possible that both digitial and analog output signals can work this way?



Andrei's picture

I am running two of these beasties.  One an ST and the other an STX.  For my part I have never had a problem with either playing resolutions of 44.1, 48, 96, & 192.  Sound quality was already good and took a giant leap forward when I upgraded the op-amps (a very cheap exercise).

Now the tricky subject of resolutions of 88.2 Khz and 176.4 Khz.  In fact there is a workaround.  If you have the free Audacity software it can be done.  Audacity is one of those freeware programs that are just outstanding.  What you do is this: (1) you simply load the track to be played.  (2) you play it back in Audacity.  So you do not use Foobar or MediaMonkey or Windows Media player or the like.  Now here is the curious thing: when using Audacity for playback it actually sounds better than even Foobar, my current favorite.  Audacity is a progarm for manipulating sound, rather than playback, but it naturally has a playback feature so you can hear the effects you have done.  What I think is happening is this:  Audacity rips the track into memory as some sort of wav format and hence the bit-rate / resolution is no longer relevant.

While I am on this subject: I found a small improvement by running a co-axial into a dedicated DAC.  This is not really necessary and hardly justifies the expense because the Xonar ST and STX already have excellent DACs.  The cost is a lot because you will need not only a better DAC but the cabling has to be good too.

Mirko's picture

Thanks for the great and informative review.  I bought this sound card with the intention of streaming spdif out to my pioneer 09tx so I could listen to high def FLAC on my stereo system.   I had no idea that the quality of the card actually makes a difference when using spdif out.  Which is contrary to what most people write about spdif.  Often you read that it doesn't matter and that bits are bits.  But i found this actually isn't the case.  If you don't believe me, try for yourself.  I thought I could live w/ my motherboards Realtek spdif out to my receiver and let the receiver  do the decoding.  But noticed that My realtek spdif sounded like crap!!! ESPECIALLY when comparing against the sound files the receiver decoded from usb or the ipod dock.  So I considered an external DAC, but I know that my receivers dac uses wolfson 8741 chip which Is already good. Anyway, after hooking up this asus bad boy, i was blown away by the worldly difference in sound that it made.  Setting the output on the card to PCM 192khz and I'm all set.  Mission accomplished.  But that's not all.  After comparing the analogue sound of the card, i was again, quite impressed...which one did i like better? My receiver to decode or the asus PCM chips?  i did A/B comparison with the asus doing the decoding versus the pioneer by running a long 1/4" jack and setting the volume level the same between the two.  Let me tell you, for 200 dollars, this asus card does a seriously good job providing a crisp clean and open analogue signal to your ears. I still prefer the my receivers dac by wolfson chips.  The sound is a little more smoother and less harsh to my's different but not better.   But I killed two birds with one stone on this one.  For two hundred dollars I got an excellent digital transport to my receiver, and high end audio analogue outs from my computer that are clear, clean an extremely quiet.  Very happy customer here.  To think that there are people out there running spdif from  crappy cards to thousand dollar external DACS is sad to me.  Maybe I'm wrong..anyway.  Awesome card.  Awesome buy.  Killer sound.  Makes me wonder if I would be able to discern the difference from this card and the essence one.  


Andrei's picture

Hi Mirko

I agree the sound quality is really good.  My other Source is a Cambridge Audio 650BD (not counting a turntable). Overall the Asus Xonar ST eclipses it by a tad.  The comparison is a bit tricky though because (i) I have upgraded the op-amps; (ii) the CA 650BD does play DVDA and SACD.  But on an Apples to Apples Comparison CD vs Flac at 16bit 44.1 Khz : the Asus Xonar card is a smidge better.  It becomes even better when I play flac files at 24bit and 48, 96, and 192 Khz.  On the other side the CA650BD is a bit better when playing DVDA and especially SACD.  The CA 650BD is not high-end to be sure but it is not bottom end either.  I think for 'spare change' the Asus Xonar cards are simply fabulous.  Why anyone would buy a Music Sever when they can have this card?

Initially I used the RCA connections direct to the AMP.  Then I tried SPDIF optical, and USB into an external DAC.  Finally I tried SPDIF coaxial into an external DAC.  USB was easilly the weakest and SPDIF via co-ax is easily the best sound quality.  The caveat is that you do need good cables.  


Andrei's picture

Oops.  Ignore the USB comment above.  I actually have two of these soundcards, or rather an ST and an STX.  With the STX that I use in my office it is connected to Bowers and Wilkins MM1 Desktop speakers.  They have the USB connection option to the PC.  With this Soundcard I connect via a RCA to Stereo plug.  It is this USB connection that I had tried and is not as good as using the Asus Xonar soundcard.


hollowman's picture

Selecting 192k Sample Rate in Xonar's Audio Control Center gives best performance of std. 16/44.1 in my tests. Wish the Control Center allowed more direct DAC control, such as selectable digital filter (Slow/Sharp) and phase reversal. 

Agree that this Card is a decent value. Since Asus decison-makers (and Asus' direct competitors, like HTOmega) are probably reading these comments, here are three suggestions for future products:

1. Use dual DACs in diff mode

2 Use better DACs, such as ESS Sabre

3. Design/offer more advanced firmware filters (prefer. user selectable) and upsampling. This may be via decoder DSP or simply selecting amongst those innate in DAC chip. E.g., Min. Phase, Apodizing, etc. Also allow selectable upsampling.

That's all! #3 requires no costly PCB/topological redesign -- it's just software code re-writing. #1 and #2 can be done w/o too much PCB redesign. The Sabre chip maybe $20-30 more, but I'll be glad to pay that for the huge gain in performance.

Thx for your attn.!

Shalmaneser's picture

I'm looking for cable advice for my Essence STX II -> Yamaha CX A5000 connection. I don't have anything local for easy comparison. I don't go for marketing of oligonucleotides injected into titanium mono-filament cables jacketed with carbon nano-fibre woven kevlar bulletproof sleeves. (lets keep it somewhere under $6 a foot.)

Shalmaneser's picture

Does anyone have a guide to the various opamps that are usable in the STX II? I can't even find anything that characterizes the included/extra opamps that ship with the STX II. Thanks!