Listening to Music
The Xonar D2, a very top-class product, will be compared with the best non-professional sound cards available today, Creative X-Fi Elite Pro and Auzen X-Fi Prelude 7.1. To evaluate the sound quality I use Grado SR 325i headphones together with a C.E.C. HD53R Ver.8.0 amplifier connected to the sound card with a Monster Standard Interlink 200 cable. I use recordings of various genres saved from CDs in wave format. My players are Foobar2000 0.9.5 and WinAMP 2.95. The same volume (2dB RMS) is elected for every sound card in order to get the largest dynamic range. I disable the replay gain in the Foobar options; the sound is reproduced via DirectSound in 32-bit format. WinAMP is used together with the ASIO output (dll version) 0.67 SSE2 plugin.
I describe the versions and options so thoroughly because I noted in the Auzen X-Fi Prelude 7.1 review that not all players or sound output plugins could reproduce reverberations and the spatial localization of sounds correctly. My setup is more or less correct. The choice of the software player is important for sound cards of such a high class. For example, the version 0.9 ASIO playback plugin for Foobar works inaccurately which can be easily demonstrated with measurements.
Intermodulation distortions when reproducing sound
via ASIO with different players. Digital loop, 44.1kHz, 16 bits
My first experience of listening to music on the Xonar D2 with the included driver was not very pleasant. Its sound was overall very clear and detailed but lacked the necessary depth and saturated overtones. I’d call this sound faded, colorless. The sound scene was broad but flat, without echeloning, which deprived the music of all the pleasure. Fortunately, the programmers found the error and it’s all much better with the current driver.
The card is admirable for its deep and dynamic sound. I am very impressed at the reproduction of minutest details against a loud background, which is especially conspicuous in the rich sound of violins, also in a large orchestra. The timbres of other musical instruments are quite natural as well; the medium and high frequencies are clear and detailed, the bass is sharp and saturated. But with all these advantages, the sound sometimes lacks space and aftersound, and the natural reverberations are quickly lost in the overall “mass”. So when there are many instruments playing simultaneously, you often feel the music is not really detailed. You can hear this quite distinctly in comparison with the Auzen X-Fi Prelude which is very delicate about the acoustics of the environment. The space, the realistic voluminosity even for the bass, the superb detailedness and microdynamics in the top register which yields highly natural timbres, make the Prelude the best choice for jazz and other live recordings. The Xonar differs from the Prelude with harder top frequencies but better macrodynamics, which makes it preferable for listening to Judas Priest, for example.
The Creative X-Fi Elite Pro sounds energetic and very detailed but its stiff and developed bass is accompanied with biting high frequencies while its medium frequencies are unexpressive and colored: after the ASUS Xonar D2 most instruments seem to play half a tone higher. The colorings from several instruments mix together to create a kind of a high-frequency coating worsening the spatial resolution. The reflections of high-frequency sounds from the walls of the studio recorded in the composition lose their individuality and merge into the original sound producing an odd result. I heard such unpleasant sharpness and aggressiveness before on my good old Audiotrak Prodigy 7.1 which still resides in my PC thanks to one accidental discovery.
Reading through the documentation on the Wolfson WM8770 digital-to-analog converter I noticed how greatly the digital filter characteristics varied at different sample rates. I tried software resampling (SSRC) of recordings into a sample rate of 192kHz and then into 176.4kHz (a multiple of 44.1kHz, the standard sample rate of music). I was highly pleased at the result: the sharpness disappeared, the scene became larger. With such a sound I didn’t want a more expensive sound card! Later on, when I dared to replace the opamps, I found an interesting thing: resampling didn’t provide any advantages with opamps faster than the default NJM4580. The Creative X-Fi Elite Pro has NJM2114 opamps, similar to the NJM4580 in characteristics, in its front output, so I decided to try software resampling once again.
Creative’s X-Fi series cards do not support the highest sample rates in the Audio Creation mode, so I had to limit myself to 96kHz, but that was enough for the situation to improve. There is less coloring and the high-frequency coating nearly vanishes from the scene. Medium frequencies are more detailed. First I used resampling in the ASIO output plugin for WinAMP but later I just set the necessary clock generator frequency in Creative’s mixer settings utilizing the card’s hardware resources for the process. The result was the same. In the Entertainment mode where stereo recordings are always converted into 192kHz, with the equalizer, Crystalizer, CMSS and SVE disabled, I achieved an even clearer and lush sound at the expense of a minor loss in spatial precision.