Review: ASUS Essence STX II 7.1 Sound Card

alcor 468x60 Review: ASUS Essence STX II 7.1 Sound Card

PC audio is getting more popular among audiophile group and PC enthusiasts. Plenty of them are shifting to CAS ( Computer Audio Source ) as the sources are easier to grab with internet access. ASUS did very well in the audio hardware, since their flagship Essence series 4 years back. Recently they just announced the new ASUS Xonar Essence STX II which is the highest-end model of PCI-e sound card.

First of all, we would like to thank ASUS for providing us the sound card for review. Essence series is the high-end range of audio products from ASUS. After releasing the predecessors Essence ST and Essence STX, they released three other external USB DAC/amplifier models which include the Essence III, Essence One, and Essence STU. The Essence STX II is consisted of two versions. One is the Essence STX II 7.1 which we will be covering in this review, and another is Essence STX II which comes without the 7.1 daughter board.

Product Link :
Suggested Retail Price: RM 999




The packaging is more or less the same as the previous Essence STX. A very premium packaging by ASUS which is quite necessary for this premium priced product.


The rear side of the box, showing all the features of the sound card.


Fold up the box cover, it barely explains all the components and connectors on the PCB.


The Essence of Sound. The purpose of naming it “Essence” is primarily meant to deliver state-of-the-art products for the audiophile.


The sound card and the accessories box below.


Here’s the Essence STX II sound card itself which comes with a beautiful heatsink illustrated with the tiger logo.


Inside the accessories box, we have user’s manual and driver CD.


The Op-AMP swap kit which consists of a clamp tool and 3 extra Op-amps. Inside the user’s manual there’s a detailed guide to show you how to swap the Op-AMP.


Besides that, other accessories included like daughter board bridge connector, 6.3mm to 3.5mm converter, and 3.5mm to RCA cable converter. The daughter board bridge connector is a little bit looks like the old IDE cable.


The daughter board which comes exclusively for the Essence STX II 7.1 model is also known as the Essence H6. That’s the only difference that distinguished between Essence STX II and Essence STX II 7.1 editions. So as expected the Essence STX II is selling cheaper than the Essence STX II 7.1 edition.


The Op-amp swap kit. 2 Muses 8820 op-amp and 1 low pass filter which allowed enthusiasts to switch the sound signature to their own preferences. As for the original op-amp we will discuss it further later.


Here’s the soundcard with the heatsink dismantled. You can see that there are a lot of golden capacitors soldered across the PCB.


The audio chipset, ASUS AV100 HD Audio Processing Unit. With the Digital Signal Processing (DSP), the sound card converts the digital samples of audio files back into analog waves which is then emitted by your speakers.


ASMedia ASM1083, x1 PCI Express to 32-bit PCI Bridge. This is the bridge controller that allows users to connect legacy parallel bus devices to the advanced serial PCI Express interface. PCI has a better power delivery for audio related hardware compared to PCI Express x1 due to the lesser interference in sin wave.


Muses 8920 Op-amp. The original Op-amp pre-installed in the sound card. For audiophile enthusiasts who love to play with the op-amp, they can easily switch it with the Muses 8820 or any op-amp that they desired.


For a premium price that you paid for, you get high quality golden capacitors. Capacitors are to “temporary” store the energy and it will makes the rectified Alternative Current (AC) smoother and provide adequate regulation to achieve the variable demands of the music singal in every amplifying stage.


Here we have a connector that connects the daughter board to the main board with the included cable.


Essence STX II requires 4 pin Molex connector to power it up.


In order to use the front panel audio connector, you’ll have to connect casing front panel I/O port to this front panel header.


For the connectivity of the soundcard, from the left first and second is the RCA connector for active speaker. 3rd connector to connect a headphone and 4th one is for microphone. The last one S/PDIF is for external DAC or home theater system.


Back of the PCB. It’s fully black and it looks good in aesthetic wise.

And they are connected together!


Before go into the sound testing, we take a look at the Essence STX II software which comes in the CD, Xonar Audio Center. Unfortunately there’s no additional features on the Xonar Audio Center compared with the lower end series sound card by ASUS.

The main menu of software. Basic equalizer, volume control and you can select the DSP Mode at the bottom right corner. There are 4 options to choose, movie, music, game and Hi-Fi. Turn on any of these will activate the Dolby Pro Logic IIx and Dolby Virtual Speaker except for the Hi-Fi option.

For more advance options, you can configure audio channel and your speaker setup. If you are headphone user, the SPDIF Out allowed you to set your headphone to 7.1 Virtual Surround Speaker.

This is pretty straightforward, which is the left/right volume control. Besides, the Record tab you can control your Mic recording volume as well.

Environment setting and equalizer tuning. Different environment can produces different sound effect, you are able to tune it to the one which best suits you. While the equalizer you can tune accordingly with your audio genre.

With this KARAOKE feature, you can shift the key and cancel the voice of the vocal or adding some echos to the microphone.

Flexbass allowed you to adjust the bass frequency and transfer to the subwoofer.

VocalFX makes gaming and online chatting more lively and attractive.



When it comes to audiophile testing, there is no figure data to benchmark and judge how good is the product. So the results we get here can be very subjective to other users.

In our test, we will compare the Essence STX II 7.1 with ASUS Maximus V Formula onboard audio chip, SupremeFX IV. The audio equipment we’ll be using is 2.1 speaker from Acoustic Energy, Aego M. As for the Op-Amp, we keep the original Muses 8920 on the sound card. All the audio file in our testing is FLAC.

Hotel California - Eagles

With SupremeFX IV, the mid bass is too excessive and poorly damped low frequencies. The sound is kinda textureless and liquid.

Essence STX II 7.1 produces very warm sound, the bass is punchy and adequate low frequencies. During high mids, the sound is easy on the ears, not really harsh.

It’s so hard to say goodbye - Boyz II Men

On SupremeFX IV the song had too much high frequency response and it’s sounds like nearly distorted. This song are mostly vocals and it was kinda muddy with weak harmonics.

Tested on Essence STX II 7.1, the vocals and instrumental playing behind are much tonal balance. The song became more transparent, detailed and easy to hear into the music with wide flat frequency response.

Last part of the test, we try to provide some numerical benchmarking. We downloaded an Android app called Sound Meter to monitor the decibels of the sound produced by both. At the same speaker volume level and the Android device placing at the same position, below are the results we got.

SupremeFX IV

Essence STX II 7.1

From the result we can see that Essence STX II 7.1 can significantly amplified the output volume without any tweak.



ASUS did very well in developing their Essence series as they brought up the trend in computer audio. ASUS Essence STX II 7.1 sound card is a very good kick start for those who going to step into audiophile world, there are more expensive external DAC but in this price range Essence STX II 7.1 performance is outstanding. With the option of extra op-amps, enthusiast can enjoys the DIY progress and test the op-amp one by one. The daughter board Essence H6 gave more connectivity options to users.

ASUS Essence STX II 7.1 is available now at RM999. For multimedia audiophile setup, you can’t get anything better than this to pair with a good multimedia speaker and gaming headphone.

Performance: 5/5
Materials: 5/5
Specifications: 5/5
Appearance: 4/5
Performance/Price Value: 4/5

+ High quality materials
+ Great performance
+ Good looking heatsink
+ Comes with another Essence H6 daughter board

- Daughter board bridge connector makes the system look messy
- Price that not much users willing to spend
- No improvement in software

ASUS Xonar Essence STX II 7.1 received Gold Award from

Disclaimer: gives out our own award based on the Hardware Performance, OverClocking Ability, Innovation, and Value as determined by the reviewer


Writer, Reviewer at
A very down to earth Power User striving to make a name for himself and very passionate to the DIY PC industry. Starting to gain attention with his reviews on Chassis and Gaming Gears.

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