Effortlessly fill any living space with the power of incredible, true stereo sound that brings your listening experience to life. An all-access pass to ALL of your music on any app or device, the HD4 offers wired or wireless connections including USB input from your computer, Bluetooth aptX-HD from your phone, tablet or computer, or good old analog from that turntable or prized tape deck. The HD4 system also features a high-quality headphone amplifier for private listening.