Asus Xonar U3 is currently the cheapest USB soundcard from Asus. Made for the person that wants better audio quality on his notebook/laptop for music,movies and games.
The Xonar U3 Features a Built-in Headphone amplifier, two 3.5mm minijacks one for headphones and the other for a microphone. The Xonar U3 also features Asus' GX2.5 technology for surround sound in games and a S/PDIF TOSLINK optical adapter to allow connection to hometheater systems or external DAC's a lot easier.
The Xonar U3 is surprisingly large in size, for a "usb stick" sized Soundcard, I had to use the supplied USB extension cable to get the Xonar U3 to plug into one of my available USB slots. It also features two Blue LEDs which serve no purpose other than showing when the Xonar U3 is powered on. One LED would have done this job just as well.
I initially bought my Xonar U3 as I was looking for a value for money upgrade to my onboard soundcard on my Desktop PC which uses the Realtek ALC889 codec, mostly for recording my Let's Plays and other youtube videos. But sadly the Xonar U3 performs a bit worse than the Realtek ALC889 in that regards, as it has a fair bit of static. Even after updating the drivers and trying out various USB cables.
Where it does beat the Realtek ALC889 though is when it's driving a set of headphones, as the Realtek ALC889 has no built in headphone amplifier, I have to add though don't expect the Asus Xonar U3 to do a decent job of driving a set of high end headphones like the Sennheiser HD800s, but it does do a decent enough job driving entry to mid level headphones, from the Sennheiser HD201's and AKG K77's to the Pioneer SE-A1000's and Sennheiser HD555.
While the Asus Xonar U3 has Dolby Digital technology, I find that for movies it doesn't really do a good job. And Music also isn't it's forte. Where it does shine though is when it comes to Gaming. The simulated surround sound works surprisingly well. Especially regarding how cheap the Xonar U3 is.
All things considered, at the price point of the Asus Xonar U3, if you are looking for an upgrade to your notebook/laptop's audio for whatever purpose. It's not a bad purchase, though it's not worth it if you need a replacement soundcard for your Desktop rig, rather look at the internal soundcards or an External DAC.
I for one will stick to my Realtek ALC889's microphone jack until I find a decent internal Soundcard or USB microphone. And the Asus Xonar U3 will be moved to laptop audio use for when I'm traveling.
Full Specifications are as following :
Output Signal-to-Noise Ratio (A-Weighted) (Front-out) :
Output THD+N at 1kHz (Front-out) :
<0.005 %( dB)
Frequency Response (-3dB, 16bit/48KHz input) :
20 Hz to 20 KHz
Output/Input Full-Scale Voltage :
Audio Processor :ASUS UA100 USB Audio Chip
Sample Rate and Resolution
Analog Playback Sample Rate and Resolution :
48KHz @ 16bit
1 x 3.5 mm jack (1/8") (Analog out)
1 x 3.5 mm jack (1/8") (Line-in/ Mic-in combo)
1 x S/PDIF out (1 x Optical (Toslink)/(combo with analog in))
Dolby® Technologies : Dolby® Digital Live/Dolby® Headphone /Dolby® Virtual Speaker /Dolby® Pro-Logic II
Smart Volume Normalizer™
Xear 3D™ Virtual Speaker Shifter
10 -band Equalizer
27 Environment Effects
GX 2.5 Game Audio Engine
S/PDIF optical adaptors x 1
Driver CD x 1
Quick Start Guide x 1
79.5 x 30.6 mm ( L x W )
Bundled with an Extension USB Cable