The Asus Xonar D2 was widely considered to be a successful entry into the sound card market for Asus, offering a powerful multi-purpose card designed to appeal to both gamers and budget music production. Following on from this debut, Asus has released its first USB audio device, the Xonar U1.
The U1 has a distinctive round metal knob design far removed from the typical black plastic box. Not only is it visually appealing, but it looks solid and manages not to feel like a budget device.
The top half acts as a volume dial providing a pleasingly tactile way of controlling the sound. Pressing down mutes or un-mutes the audio. There are only two audio connections, both mini-jacks. One acts as a line in or microphone input (selectable in the software mixer), the other is an analogue stereo output intended to be used by headphones or speakers and doubles as an optical out for Dolby Digital (& Live) and DTS.
Whilst the unit itself is a comfortable size, the USB cable is very short, which could be an issue if being used with a desktop computer or laptop with little desk space. The cable is directly attached to the device so at least it's not something that can be forgotten if it's to go travelling with you. Also somewhat uncomfortably small is the recess for the headphone and line jacks. My Grado 60 headphone cable just about squeezed in but not my jack to phono lead which proved too chunky.
In terms of functionality, the device offers a similar set of abilities to its PCI counterpart, but with only the two audio connections it is considerably less flexible. So once again you get a flurry of ®s including Dolby Headphone, Dolby Virtual Speaker, Dolby Pro Logic IIx, Dolby Digital Live, Xear 3D Virtual Speaker Shifter, etc. I've written before how I'm not a fan of processing sound to make it appear as surround on headphones or two speakers. All of these technologies rely on altering the phase of the audio signal, which interferes with the precision and clarity of the stereo mix and tends to add phasing artefacts.
As the U1 has only a digital out, the benefits of discrete surround sound will only be available if you optically connect the U1 to a surround decoder box. Presumably this is a cost issue but I would have thought including surround analogue outputs onboard, or via a breakout cable like many of Creative's offerings, would have made it a more attractive option, particularly for home theatre users. However, if your amp does have a decoder then Dolby Digital Live will let you enjoy games in surround sound without the need for a spaghetti junction of wires.