Although listening to music on the computers is something we all do these days, and there has been an explosion in the growth of laptops and mobile computing, the speakers available on most of today’s laptops leave a lot to be desired. A British company called NXT has come up with small, portable speakers that give good quality sound, and can be powered by just the USB outlet.
Most audio amplifiers – the kind you plug into the wall – maintain a voltage of about 32 volts. That means when the music gets loud, the amp can deliver the required punch. Laptops, which must use power sparingly to preserve their portability, don’t pack nearly the wallop; a USB 2.0 port produces a maximum 5.25 volts to external devices, making it impossible to power larger, high quality speakers from a laptop.
Some engineering trickery from NXT circumvents these problems by relying on the simple premise that the USB can deliver 5.25 volts all the time, even though music is not all crescendos. During quiet passages, a pair of capacitors stores unused voltage coming from the USB. The speakers monitor the music signal a few milliseconds ahead of amplification so they can release that stored up power when the interlude is over and the heavy guitar/drum combo us unleashed.
Of course, this technology is a replacement for weaker bus-powered, desktop-style speakers; pretty much any high-quality stereo speaker has an AC adapter. And the power storage is limited; the extended version of Freebird could run the capacitors out of juice, causing the volume to fall. But NXT says they’ve tested the speakers on a variety of musical styles with consistent success. If they can get some consumer electronics firms to hear them, the technology could be on the market by next year.
Source: Popular Science.