PCIE版本的老虎卡的2声道做的算是不错了，但其PCI to PCIE桥接芯片却让玩家诟病不已，
对多声道支持不够好也是其致命伤，现在Asus将要推出PCI版本老虎卡Essence ST，
在保证原有2声道输出音质不变的情况下又加入了6声道扩展子卡，
子卡每2声道一颗DAC，全运放输出，模拟RCA接口，用了规格貌似基本同主卡的2声道，
极大提升了多声道影音输出的质量，大大方便了中高端PC音频视频玩家！
虽然说Asus做声卡还刚起步，但把在主板上的发烧/极限精神用在了声卡上，
而且价格也不算贵（主卡价格不变，子卡价格未知），因此这不得不说是我们的福气！
当然，现在还是ES版本，期望Asus最终Retail出来的时候规格不降反升，哈哈
以下转自Guru3D：
Hey there my fellow audio junkies. The PC audio market has been churning out some great new high fidelity soundcards lately. A good example here is the recent release of the new Essence STX headphone card, which stirred up the audio community and caught the attention of people who usually look for external headphone amplifiers. The specifications, component choices and overall sound quality of this card cannot be ignored. The Essence STX is one serious soundcard offering some amazing sound quality for the end users.
Quite a good amount of you audiophile guru's may know there were rumors of
ASUS expanding the Essence Line-up with possibly a
PCI model.
Well audio crazies we have the engineering sample of the Essence ST in ours audio lab today!
Ladies and Gentlemen and audio crazies alike allow us to present the new Xonar Essence ST. Let's take a look at this new sample straight from the ASUS labs, this baby is so fresh you can still smell the solder dampening off the card with fumes that could be seen as
music notes ...
Whoa, now that is a nice looking piece of audio technology. The original Essence STX offered a lot of great sound quality and audio options for the price. However, the lack of analog surround was disappointing to some and some felt it made the STX more a niche card meant for a specific market then a full fledge flagship audio product meant for the masses.
The New ST's main feature is the new pin header which allows the card to connect to the H6 DAC
expansion card which can currently be seen bundled with the HDAV 1.3 Deluxe.
With the addition of this pin header the new ST has more diverse repertoire of features and output audio options available to users. Between the STX and the upcoming ST, the Xonar sound machine will become much more diverse for headphones users and high end speakers users alike. Let's have a look and see what we have under the shielding.
There are some basic differences between the two cards but it seems what makes the STX a serious
audio card is also present on the Essence ST.
Let's have a closer look at this new card to see what it has to offer.
We have the high quality Burr Brown DAC on the base card and the exact opamp configuration which has been happily received by the serious and novice modders in the community. We can see high quality Nichon and Os-con audio capacitors used throughout the design.
The H6 DAC card has a different DAC measured for about a 120 SNR (Signal to Noise Ratio). The entire card has the three opamp configuration per stereo pair. Stock, this card offers two JRC 2114D opamps used for a differential input Current to Voltage (I/V) converter section followed by a LM4562 used as a single ended buffer amplifier.
This opamp configuration not only allows you to install higher quality units but also allows you to tune certain channels more to their duty. For instance there is a separate I/V opamp for the center and
subwoofer outputs. You could use a 2107 for increased clarity on the
center channel and install an OPA2227 for better bass response for the subwoofer channel. You could use your personal favorites for these positions as those are just suggestions but you can see the possibilities for fine tuning this card.
Variances from the STXWe are still waiting for confirmation on a few design aspects of the card as there are a few differences aside from the pin header. We would rather wait until we have solid information regarding a few of the components before we release them to our readers. Let's have a look at both cards side by side:
We have the Essence STX to the left hand side and the ST engineering sample to the right. We do understand this card is said to have a different clocking circuit from its predecessors but are waiting for more information on the specifications of the new part and resulting circuit. The ST also doesn't need the
PCI Bridge chip as the AV100 is a native PCI interface audio controller chip.
Preliminary listening testsWe have tested this card with a few sets of headphones, speakers systems and studio reference
monitors. This card has some serious sound quality for headphones and speakers systems. The card has a similar
sonic flavor presented by the Essence STX however, there is something a little different about the response. The ST has a crystal clear ultra detailed sound combined with warmth and articulation for bass, mids and high frequencies alike.
This card was auditioned for those who came around and all were impressed with the sonic prowess of the upcoming Essence ST.
Final Thoughts and preliminary verdict
The ST version was always meant for the PCI users however the new design changes are a welcome addition for many users. The addition of the Pin header will allow the Essence ST card to reach a much larger audience and allows the card to perform a wider variety of audio tasks.
We should note that this design is still on the drawing board and what will or will not be bundled with the final version of the card has not been solidified yet.
The engineering sample was bundled with a H6 DAC board but who knows; maybe ASUS will produce another
expansion board for this card with different DAC's or a totally different output card. With the addition of the pin header there are some great
design options open the cards designers. We will be further testing this card and offering new information and testing results as they become available.
Now then, I have to get back to listening to the Essence ST 
