Performance

The performance of the ASUS Xonar Essence One is tested both via listening tests with a barrage of headphones and a set of RMAA tests carried out by hooking its headphone out up to a ASUS Xonar Essence STX sound card with the latest drivers installed. The STX was setup according to the guide on RightMark’s webpage.

RMAA

RightMark Audio Analyzer is by all means an obsolete piece of software, but it still provides good enough results to be able to judge some of the core qualities of a DAC and headphone amplifier. The Essence One provides a neutral output and features a cut off at the 20 kHz mark. It is linear all the way to the bottom of the audible spectrum in an unloaded scenario. All measurements give the unit a score way above average and all the measurements are in line with what you would expect from any high-end DAC and headphone amplifier combination.

The sound card used for the test was an ASUS Xonar Essesnce STX which of course has its limits when it comes to measurements. The measurements provided by ASUS in their Audio Precision report concurs on a number of aspects with what we saw on the RMAA test, except for the THD + N measurements which Audio Precision reveals is in the range of 0.000316% (-110 dB) the discrepancy is most likely due to RMAA in conjunction with the Essence STX.

Listening Tests

Before any listening was done the unit was updated to the latest firmware, this process is a bit tedious since there are essentially two sets of firmware on the device. One for the USB receiver and, one for the rest of the unit. After the update was done the unit was allowed to play for 100 hours before any critical listening was done.

For this particular test we brought out the big guns to see what this unit it capable of, the following headphones were used for testing: Sennheiser HD600/HD650/PX-200II, BeyerDynamic MMX300 (DT770 32 Ohm version), HiFiMAN HE-6/HE-500/HE-400/HE-300/HE-5LE, Westone ES5/W4R, Ultimate Ears In-ear Reference Monitors, Jerry Harvey Audio JH|16Pro, Fostex T50RP (slightly modded), Grado SR-60 (slightly modded),

Since ASUS is kind enough to enable op-amp swapping on their higher end headphone solutions we thought it would be fun tryout LM4562s and OPA 2604AP instead of the stock NE5532, and AD 797BRZ instead of the LM49720NAs.

The Essence One brings a lot of neat features to the table. For one it has 192 kHz 24-bit playback (4.35 times the resolution of a CD content) and features a well implemented USB interface. In order to kick off our testing Foobar 2k was fired up and ASIO drivers configured to get the most out of the unit. Even straight out of the box the Essence One proves to be an entertaining piece of kit. Through ASIO support the unit can change sampling rate per track in Foobar almost instantaneously which is great since HD music files rarely feature the same sampling rate. In our test library we had content mixed across the following sampling rates: 44.1, 88.2, 96, 176.4, 192 kHz (16/24-bit). The Essence One eats them all without any issues or awkward artifacts appearing which is to be expected of such a relative high-end piece of kit. It does have a slight pre track judder sometimes but that is most likely due to Foobar 2k and its ASIO plug-in.

With the standard op-amps installed the unit simply outdoes the HiFiMAN HM-801 on all accounts, right from 44.1 kHz to 96 kHz which is the highest sampling rate the HiFiMAN player can handle. Sonically the two units are very different sounding. The HiFiMAN has an early roll-off which gives it a somewhat soft sounding high-end, bass control is tremendous with both units and the HiFiMAN player's balanced module gives the ASUS Xonar Essence One a real run for its money bass definition wise. Comparatively the midrange of the Essence One is more detailed albeit slightly less spacious sounding with the stock op-amps in the unit. Both the HiFiMAN HM-801 and the Essence One is capable of driving quite demanding headphones like the Sennheiser HD650s and the HiFiMAN HE-5LEs without breaking a sweat, however, the Xonar Essence One provides more headroom in terms of volume due to a slightly higher default gain setting.

Compared to the ASUS Essence STX sound card which is considered a good mid-end source for headphones the Essence One is just better on all accounts. The STX sounds coarser and the sound stage is a far cry away from being up to the same standard of the Essence One. These two products are miles apart in terms of sound quality, even though the STX sound good by all accounts. Depending on the headphones in use the differences vary in size. With a set of high end headphones like the HD600s or HD650s the differences are easily noticeable and the same thing goes for the HE-400/HE-500s. Going back to a set of BeyerDynamic MMX300s, Sennheiser PX 200-II and HE-300s the differences are less apparent albeit the difference in sound stage dynamics are still very present.

Interestingly enough our much loved Fostex HP-P1 proved its worth albeit being limited by only being able to decode 44.1 kHz content. Its organic and smooth presentation is up there with the HM-801 and with the filter set to option 2 you get almost the same kind of liquid like sound as the Essence One provides with the LM4562s and the AD 797BRZs installed. The Fostex HP-P1 is only let down by its detail level with 44.1 kHz source material. The Essence One is just some much more effortless in producing micro-details and delivering a coherent and spacious sound.

The gain of the Essence One is quite high making it less than ideal for use with ultra-high sensitivity in-ears. Even with the volume at its lowest balanced level we had to turn down the volume in Foobar in order not to damage our ears.

The stock op-amps are alright, the use of NE5532s for the I/V and filter stage and LM49720NA for the headphone amplification stage does the trick and gives the sound good balance. Some might find the neutral sound of this particular combination a bit boring, but luckily you can induce a warmer sound signature by opting for some slightly higher end op-amps for the filter stage and some notoriously hot sounding op-amps for the headphone gain stage.

Our first experiment with op-amps was a simple job of pulling out the NNE5532s and loading the device with six LM4562NAs and this change seemed to give a better rendition of the sound stage and a better sense of layering in the sound. Particularly the midrange definition change makes the swap well worth the extra dollars in my opinion, listening to 96 kHz versions of Bueno Vista Social Clubs "Chan Chan" really highlights the change as the two male voices in the center become so much easier to tell apart spatially. The LM4562s are definitely more transparent and smoother sounding in the ASUS Xonar Essence One.

Introducing the AD 797BRZs to the headphone stage opened up the sound a bit more, but the changes are marginal over the stock op-amp. Separation and layering was a bit better and the midrange seemed to gain some much needed warmth. The highs are definitely sweeter with the AD 797BRZs installed, but the cost of these op-amps makes it a tough call. We got our dual SOIC AD 797BRZs on DIP8 adapter for around $60, which seems to be the going rate for these hyped high-end op-amps. If you are going all in and what the sound signature of the AD 797BRZs the upgrade is alright bang-for-buck wise, but it is definitely not a must have for all users. The stock ones do a magnificent job in this particular design.

Synergy wise the ASUS Xonar Essence One will pair well with most headphones since it is neutral sounding with the default op-amps. Due to the implementation of swappable op-amps you can get the Essence One to sound just the way to want it, however, exotic op-amps will be hard to find and adds to the total cost of the solution albeit providing only minor upgrades to the sound quality.