Yamaha have just released a new USB powered speaker; the NX-U02. This single speaker contains two speakers that give you stereo sound from the single box. Yamaha uses a PowerStorage circuit that allows for 20W (2 x 10W) of power from a USB speaker.
The NX-U02 includes Yamaha’s exclusive SR-Bass technology, to give a rich bass sound and the unit is available in black, white or red. Should be available next month.