Listening to Music
I reproduced music using foobar2000 0.9.6.3 beta 2 with the latest sound output plugins. I used the same plugins for all the sound cards for the comparison to be correct since the Bravura doesn't support ASIO in any OS. The plugins were Kernel Streaming for Windows XP and WASAPI for Windows 7.
I didn’t use foobar2000’s standard output interface for a number of reasons. It is susceptible to software processing in the Windows audio subsystem under Windows 7. When used in Windows XP, DirectSound is much quieter than Kernel Streaming with the tested sound cards. As I found out later, the Wave control has to be set at its maximum in the mixer to achieve a normal volume level. I guess the reduced volume is necessary to minimize distortions when special effects are applied to audio. By the way, the special effects are not turned off in Windows XP even when Kernel Streaming is selected for audio output whereas the WASAPI interface provides additional advantages in Windows Vista and 7: you can keep CMSS-3D enabled when listening to music and do not have to worry about whether the sampling rate of the audio material agrees with the Windows settings. In other words, WASAPI saves you the trouble of adjusting the sound card’s settings and interacting with the sluggish software. This is better than, for example, the behavior of ASUS Xonar series cards which apply special effects (particularly, Dolby 3D sound algorithms) irrespective of the audio playback method under any version of Windows.
As I mentioned above, only two sampling rates, 48 and 96 kHz, are supported in Windows XP. It means that CD-DA music is always resampled, which is not good news for users who have accumulated their music collections by grabbing audio CDs. Many modern games use 44kHz audio, too. Fortunately, the resampling algorithms have improved since the SoundBlaster Live! and Audigy 2, so listening to music in Windows XP was quite a pleasure with every sound card included into this test session (considering that the latest driver version was installed for the Bravura).
The bulk of this test session was performed in Windows 7 64-bit where the sampling rate of 44.1 kHz is available both for the headphone and for the line outputs. Availability doesn’t mean full support, though, as was made clear by the integrated SoundMax audio in RightMark Audio Analyzer. Both CA0110-based sound cards are far from perfect in this respect, too. In my reviews of all ASUS Xonar series products I mentioned the fact that the sound card's SNR deteriorates at a sampling rate of 44.1 kHz. Well, this deterioration is far smaller than what you can hear with the Auzen X-Fi Bravura. The latter’s sound quality degenerates so much that it becomes a real problem when listening to music at a volume of 40% or lower. And while you can set the volume of the line outputs higher and then reduce it on your amplifier, this high amount of noise is a real problem for the integrated headphone amplifier. No other sound card I have ever tested behaves so defiantly. You can only get rid of the incessant hiss that rises up whenever you play music or launch a game by switching the card to a sampling rate which is a multiple of 48 kHz, i.e. by using software resampling. As a result, in both operating systems your music will be converted into the higher sampling rate which is hardly an optimal way of reproducing music. The Creative X-Fi Xtreme Audio also behaves like that, yet somewhat less irritatingly for some reason.
Besides a few select audiophile recordings from different test discs, I listened to Nina Simone’s A Single Woman, Roger Waters’ Amused to Death, Judas Priest’s Demolition and many others. Every sound card was switched to a sampling rate of 44.1 kHz in the Windows control panel and in the card’s own driver (the ASUS Xonar). The Auzen Prelude worked in the Audio Creation mode with Bit-Matched Playback enabled. For the rest of the cards I just turned off all kinds of sound processing. You can refer to my previous review for a description of terms that I use to characterize sound quality.
At first I compared the line outputs of the four sound cards by connecting them one by one to my headphone amplifier C.E.C. HD53R-80. As the ASUS Xonar D2 and the Auzen Prelude have LM4562 opamps in their front channels, I also installed the same opamp into the Auzen Bravura, but to a most unexpected effect.
First of all, the Bravura was very noisy. I could avoid the audible noise in its line output by raising the sound volume above 50% on the sound card and reducing it on the amplifier.
Second, its sound quality was far from impressive. While delivering good high frequencies and dynamics, it produced muffled bass and lacked details (echoes and aftersounds).
The Prelude was softer, more natural and comfortable. It sounded freer, so to say. The reverberations could be heard longer, the contrabass did not buzz annoyingly, the violins had a soul and the vocals had more softness.
The D2 had a peculiar way of building the sound scene. The bass was kind of more fluid, the high and medium frequencies were muddier, and the vocals were less distinct. The violins were rather irritating but the string instruments and the piano were reproduced excellently. This sound card did not lose resolution when reproducing polyphony.
The XA was inferior in resolution only: the vocals were less distinct and the high frequencies were blurrier and louder, which may be an indication of a higher level of distortions. The hissing wasn’t as oppressive as with the Bravura and the piano had a more impressive sound. The contrabass was sharper and more powerful and the echoes would fade out in a more natural way, even though rather too fast.
Although the inexpensive XA was inferior to the Bravura in the resolution and depth of the sound scene, in the detailed reproduction of trebles and in the distinctiveness of reverberations, it was more comfortable and exciting to listen to with most of my music compositions.
Sorted in the order of decreasing comfort and sound quality, the sound cards would have the following standings, depending on the particular music material:
Prelude — Bravura — XA — D2
Prelude — XA — D2 — Bravura
D2 — Prelude — XA — Bravura
Prelude — XA — Bravura — D2
Prelude — Bravura — XA — D2
Such unexpected results made me do some measurements to compare operating amplifiers. Renewing my tests of the sound cards a few weeks later, I found out that the Bravura's line output had improved greatly in terms of sound quality. I guess that it is the blocking capacitors in the card's line output that are the reason for the changes in the Bravura's sound quality over time. These are the tiny green Nichicon Muse that Auzen first installed on the X-Fi Forte and later on the Home Theater. All of these three sound cards have the same symptoms: the level of detail and resolution would increase and the timbres and bass would improve after a while. These non-polarized electrolytic capacitors seem to take a lot of time until they cease to spoil the sound. For example, the Bravura’s sound became clearer throughout the entire frequency range, producing a deeper sound scene. The instruments and vocals got more distinct, clear and realistic. The changes were the most conspicuous in the lower frequency range: the bass got sharper and saturated while the contrabass was not muffled anymore.
My measurements helped me find the reason for the surprisingly poor performance of the Xonar D2. This sound card occasionally enabled signal processing like what was noted in my and some other reviews.
This error is not related to ASIO and disappears when the data format for the playback device is changed in the Windows control panel. I will discuss the problem of setting up ASUS sound cards in Windows Vista and 7 in my upcoming review. Now let’s get back to the Auzen Bravura.
The final comparison of the sound cards dethroned the Auzen Prelude.
The D2 features a clear sound with quick bass and inconspicuous trebles. The only unnatural thing about its sound is the dimensions of the sound scene.
The XA puts an emphasis on bass. Its sound is kind of slower, duller but not tiresome. Its resolution is very good with an accurately built sound scene, high transparency, and an exquisite separation of individual voices and instruments. Its bass is somewhat too soft.
The Bravura was not comfortable to listen to due to an emphasis on trebles. It had less of bass, prominent top middle frequencies, and hissing trebles. The scene lacked depth, worsening the sound resolution.
The Prelude seemed to have everything in good measure, yet its sound was rather dull, pale and unexciting. Its resolution was inferior to that of every other tested card. Once again I have to confess that this card just cannot reproduce a bass guitar properly.
The DS was almost perfect with this material.
The Prelude produced a less spacious and less detailed scene. It was not as dynamic as the leader and had somewhat lisping trebles.
The XA is closer to the D2 is dynamics but has muddy trebles and a lower resolution. Its reverberations interfere with the vocals, making the latter less clear, and fade out unnaturally quickly.
The Bravura showed a good resolution at medium frequencies but lacked the absorbing detailedness of the first two cards. The vocals, piano and cymbals were rather unpleasant with this sound card.
The Bravura delivers a voluminous, incredibly clear and lush sound, especially with string instruments. It is detailed but lacks depth. The low frequencies are not stiff enough whereas the high frequencies are, on the contrary, too stiff.
The Prelude features a high level of detail, a very good stereo panorama, a clear and voluminous but rather too soft sound.
The D2 offers the most agreeable bass and an expressly voluminous sound scene. Occasionally it sounds too muddy and Roger begins to lisp.
The XA has poor depth and a low level of detail. Roger lisps occasionally.
Thus, a sound card may be the best in reproducing one musical material but fail with another. The four tested cards are roughly at the same level. There are no obvious losers among them and the quality of sound depends largely on the specifics of a particular recording. Here is another example with a couple of audiophile tracks.
The Bravura offers the richest timbre of the instrument and a voluminous sound scene.
The D2 has a detailed bottom range and a broad sound scene.
The Prelude allows to localize extra sounds and has a deep sound scene.
The XA is just good, although with a somewhat lower level of details compared to the other cards.
Piano + Male vocal
The D2 has a voluminous and impressive sound image and detailed high frequencies.
The Prelude renders soul-touching vocals but with hissing sibilants. Its level of detail is lower and the instrument has a muffled sound.
The XA has less airy and expressive, but is good otherwise.
The Bravura has a certain hiss which spoils the atmosphere. Both the vocal and the instrument lack expressiveness. The sound seems somewhat muddy overall.
I want to remind you that I reproduced the music through the WASAPI interface because the Bravura and XtremeAudio do not support ASIO. I tested the different interfaces briefly and made sure that the Auzen Prelude sounded clearer and purer via ASIO and thus would have been a leader across a lot of music materials.
I also have to note that the ASUS Xonar D2 had been modified by replacing the NJM2114 opamps with AD8066 ones. This helped me improve the card’s dynamics and get rid of an unpleasant coloring of its sound. Thus, the Xonar did somewhat better that it would have done by default, but the automatic driver-based resampling makes the Xonar the worst card in this review in many situations.