Groove is a portable headphone amplifier designed to be used with laptop computers. It draws power from the computer via USB and provides current to drive headphones. As such it is a useful sound upgrade for many users, providing the power necessary to get the most out of any pair of headphones.
The Groove is a compact and sturdy device, about the size of a pack of gum. Its solid-alloy body has a well-padded bottom to keep it from sliding around on a desk or table. Two large, rubbery buttons control volume up and down. Between them is a string of three multi-color LEDs that work together as an output-level meter that responds to dynamic peaks and dips in the audio signal.
Inside the Groove is a headphone amp and digital-to-analog converter (DAC) in one, using ESS' Sabre DAC chip with four of its converters per channel for left and right channels. The resulting digital signals are then converted to analog by the DAC amp before being sent to your headphones through the 3.5mm mini-jack port.
Groove doesn't color the sound it transmits; what goes in is what comes out. This is a major advantage over the standard analogue headphone port on most laptops, which tends to emphasize low frequencies and make music sound bright and lively. It also provides plenty of headroom for high-impedance headphones, meaning you don't run out of current to drive them like you might with a simpler DAC/amp system.