A first look at the Asus Xonar D2 Soundcard

Items	Description
Audio Performance
Output Signal-to-Noise Ratio (A-Weighted):	118 dB
Input Signal-to-Noise Ratio (A-Weighted):	118 dB
Output Total Harmonic Distortion + Noise at 1kHz :	0.0004% (-108dB)
Input Total Harmonic Distortion + Noise at 1kHz :	0.0004% (-108dB)
Frequency Response (-3dB, 24-bit/96kHz input ):	<10Hz to 46kHz
Frequency Response (-3dB, 24-bit/192kHz input):	<10Hz to 90kHz
Output/Input Full-Scale Voltage	2 Vrms (5.65 Vp-p)
Sample Rate Conversion Quality	Almost lossless, high-fidelity floating-point filters, which has: -140dB THD+N (typical value for 44.1K->48KHz, 24bit) 145dB Dynamic Range (typical value for 44.1K->48KHz, 24bit)
Main Chipset
Audio Processor	ASUS AV200 High-Definition Sound Processor (Max. 192KHz/24bit)
24-bit D-A Converter of Digital Sources:	TI Burr-Brown PCM1796 *4 (123dB SNR, Max. 192kHz/24bit)
24-bit A-D Converter for Analog Inputs:	Cirrus-Logic CS5381* 1 (120dB SNR, Max. 192kHz/24bit)
Sample Rate and Resolution
Analog Playback Sample Rate and Resolution	44.1K/48K/96K/192KHz @ 16/24bit
Analog Recording Sample Rate and Resolution	44.1K/48K/96K/192KHz @ 16/24bit
S/PDIF Digital Output	44.1K/48K/96K/192KHz @ 16/24bit, Dolby Digital, DTS, WMA-Pro
S/PDIF Digital Input	44.1K/48K/96K/192KHz @ 16/24bit
ASIO 2.0 Driver Support:	44.1K/48K/96K/192KHz @ 16/24bit
I/O Ports
Analog Output Jack:	3.50mm mini jack *4 (Front/Side/Center-Subwoofer/Back)
Analog Input Jack:	3.50mm mini jack *2 (Line-In/Mic-In)
Other line-level analog input (for CD-IN/TV Tuner):	CD-In, Aux-In (4-pin header on the card)
Digital S/PDIF Output	Coaxial and High-bandwidth Optical Combo Connector Supports 192KHz/24bit
Digital S/PDIF Input	Coaxial and High-bandwidth Optical Combo Connector Supports 192KHz/24bit
MIDI Ports	Additional MPU-401 MIDI I/O bracket and converter cable

Interesting specifications, 4x Burr Brown PCM1796 DAC... Let's take a look at more interesting stuff that will be unveiled in the following pages...

LED Audio jacks adds additional bling, and allow users to recognise the different jacks under low light conditions.

Asus Portable Music Processor Utility which allows you to add additional Dolby effects to new additions in your music library.

The LM4562 on the Xonar has improved noise rejection capabilities from PC's switch mode power supply. Improved CMRR (Common Mode Rejection Ratio) on the LM4562 removes any additional noise generated at its inputs. The JRC2114 used on the X-Fi is used extensively in electronics due to its low cost of implementation and noise rejection capabilities are low, which also means that it might be an issue when used with power supplies without careful power regulation and noise filtering.

Separate OpAmps used for balanced to unbalanced (and I/v) conversion and output used for Xonar which offers better performance, wheras the X-Fi uses a single dual-opamp for both differential and output circuit. Large possibility of reduced performance due to crosstalk.

The Burr Brown PCM1796 DAC has better SNR (Signal to Noise Ratio) when compared to the Cirrus Logic CS4398 found on the X-Fi. It has also been tested and proven in high-end Hi-fidelity electronics such as CD players. Although the CS4398 has good specifications but it would be more useful when applied in professional audio equipment.

Special attention was made on the use of capacitor type that specifically enhances the power and audio delivery paths on the Xonar, wheras the X-Fi is using one single type of capacitor for both applications.

The usage of various Taiwanese capacitors like Luxon and Jamicon non-low ESR capacitors on the X-Fi will offer moderate performance for the opamps. No film capacitors are seen, which is a pity as they can help improve transients, details and general performance of opamps, particularly those of the JRC 2114’s generation.

The usage of solid capacitors on the Xonar offers lower ESR which helps improve dynamics, details and extension for opamps. Solid caps also filter out high frequency noise better which helps as computer PSU’s generally output more high frequency noise & ripple.

The Xonar offers well defined areas for its power and audio path. It offers ease of identification of areas of interest and allows noise generated by its powers regulators be easily controlled.

Specifications wise, the Xonar really does pack a very solid punch, and beats competition hands down in every area. For now, all we can do is to wait for the Xonar D2 launch in this coming quarter...