Ok, folks, here are my complete thoughts on the new Xonar sound cards.
Xonar HDMI - This card really pushes the state of the HTPC forward, since it allows an HTPC to be fully integrated into a home theater setup where the receiver (integrated amplifier, tuner, preamplifier, signal switching) has HDMI-switching ability. The card doesn't have analog audio outputs, but that's no problem for a card that's specifically intended to be built into a HTPC and connected to a receiver via HDMI. While the Xonar HDMI has the low-profile form factor of the Xonar DX and D1, it uses the higher-quality AV200 audio processor and manages a SNR of 120dB through its digital outputs.
Xonar HDAV1.3 - When you just need more, the HDAV 1.3 card offers stereo line-level inputs as well as optical/coaxial and HDMI digital audio outputs. The card is compliant with the newer HDMI 1.3a standard, but the ordinary Xonar HDMI model appears to be as well, simply coming in the smaller form factor of the Xonar DX and D1. The HDAV1.3 also adds ASUS' Splendid HD Video processor, which provides post-processing effects on the HDMI video pass-through channel. The SNR has also been boosted from the Xonar D2's 118dB spec to a higher 120dB spec, cutting noise nearly in half again when compared to the D2 (3dB is approximately equivalent to a 2x increase). If you're building a reference-quality HTPC, this is the sound card to have, by far. However, if you want analog outputs, you'll need to be sure that you pick up the "Deluxe" version of the package, which includes the daughtercard with the entire 8-channel analog output stage on it.
Xonar Stereo, StereoX - This card from ASUS provides a new all-in-one solution for small-time digital audio workstation use, providing a TRS connection through which a low-Z microphone may be connected. ASUS manages to coax 120dB SNR from their AV100 audio processor, though the Xonar D1 and DX cards are only listed as capable of a 116dB SNR despite the fact that they use the same audio processor. I'm not sure what's goign on here. The card has a built-in headphone amplifier with up to 1 watt of drive power, which means that high-impedance headphones like my Beyerdynamic DT770 headphones (250-ohm version) can be used to fuller effect. Users of lower-impedance headphones will also notice fuller, stouter bass and improved dynamic range, as well as improved imaging. The card supports a complete set of Dolby home theater technologies, through the card's SPDIF output. However, Dolby Virtual Speaker will come in handy here -- since the card only has two output channels. Only the Xonar StereoX card was on display, but a PCI version of the card is also planned.
Xonar D1 - When we reviewed this card's PCI-Express version (the DX) in May on Techgage, it impressed us with the way that it delivered much of the capability of the Xonar D2 and D2X sound cards, and embarrassed the Creative X-Fi XtremeGamer Fatal1ty Professional Edition when it came to audio quality. It couldn't quite hang with the X-Fi in the area of CPU usage during playback of a large number of simultaneous 3D voices with EAX, but the same is true of all the Xonar audio cards due to their DSP being handled in software. The Xonar DX looked to us like a great option for a sound card upgrade, and we were perplexed at why a PCI version wasn't also on offer. Now the PCI version has arrived in the D1, and ASUS is effectively putting the rest of the sound card market on notice with what looks to be a class-beating upgrade option for older PCs.
Xonar U2W - With the Xonar U2W, ASUS adds Dolby Wireless capability to the external U2 sound card, creating a means of transmitting high-quality audio between rooms. While the external audio processor only offers a SNR of 100dB, the ability to stream audio between rooms is a benefit that can't be overlooked, which is why this is such an exciting new product.
