The range of music available from today's smartphones, tablets and computers, as well as online music services, offers an endless supply to explore and enjoy. Because of all these digital sources, we designed the Hampden's USB input to bypass the lower quality digital-to-analog converter built into most computers. A higher quality converter in the Polk Hampden optimizes this critical function for the best audio possible. The latest advances in Bluetooth wireless technology with apt-X® to ensure the music on your smartphone or tablet, and other compatible devices, is delivered at near-CD sound quality. This combination of drivers and enclosure creates a rich, warm sound much like a pair of bookshelf loudspeakers.