We've seen a few external USB audio devices in recent years. Generally they look like a small box with a number of mini jacks for your speakers and possibly digital output too.

The Hercules Gamesurround Muse Pocket USB device is anything but boxy. It has an aluminium housing that doubles up as a volume control knob with the mini jacks arranged around the base. It uses a Sonix USB controller chip, but has similar specifications and functions to the Muse 5.1 PCI card, which uses the CMI-8738 chip.

Essentially that means you'd be interested in the Pocket USB if your notebook only had stereo capability and you wanted to connect up a set of 5.1 speakers, in which case you'd probably want optical or coaxial S/PDIF output. With the Pocket USB, you're limited to using three analogue mini jack connections.

Installation is quick and simple, as you expect with a USB device that has a captive cable and no power supply. The rotary volume control knob is a good idea, as USB devices bypass the volume control that is built into DirectX, but it is poorly executed. It has no notches or stops, and it takes a couple of full rotations to cover the full volume range, which makes it tricky to work out where you are in the adjustment range. Also, as you adjust the volume, some pops and clicks are noticeable.

We were disturbed to find that, when we accessed the files on a USB memory key plugged into our Windows XP notebook, the Pocket USB vanished halfway through the MP3 it was playing, and we couldn't find the Hercules device until we restarted the notebook.

We were also unimpressed by the software package, which seems to offer nothing over Windows Media Player.

Contact: Hercules
http://europe.hercules.com

Specifications:

• Sonix SN11116 USB audio controller, Via Vinyl VT1616 AC97 codec
• 16bit/48KHz recording and playback
• 5.1 speaker output
• Outputs: mini jacks for stereo headphones, stereo microphone and stereo line-in
• 5.1 channel mixer, Hercules Media Station II
• Three-year warranty