ASUS Xonar U5 5.1 USB sound card

Compact USB audio device

The ASUS Xonar U5 is an external sound card that delivers 5.1-channel surround audio over a single USB connection. It targets laptop owners and small-form-factor PC builders who want multi-channel output without opening the case or installing a PCIe card. The unit draws power from the USB bus, so no separate adapter is required. Mac users gain plug-and-play stereo playback on OS X without installing drivers.

Fits via USB and frees expansion slots

Because the device communicates over USB, it needs only a spare Type-A port and works on Windows 7, 8, 8.1 (32-bit and 64-bit) and Mac OS X. Four 3.5 mm analogue outputs handle front, centre-subwoofer, rear and headphone channels, while a combo 3.5 mm jack accepts line-in or microphone signals. A coaxial S/PDIF output adds a digital path for external decoders. The external box layout leaves internal drive bays and motherboard slots untouched.

Steady output with 104 dB SNR

The C-Media CM6631A processor maintains a 104 dB signal-to-noise ratio during extended playback sessions at 24-bit 192 kHz resolution. USB bus power keeps the circuit stable without an external brick, and the bundled Sonic Studio software lets users adjust equalisation, virtual surround and headphone gain on the fly. The aluminium-top chassis helps dissipate heat during long gaming or media marathons.