The Audioengine P4 (AP4) is a high-performance bookshelf speaker pair with the same great looks and sound as our powered speakers. Experience the signature Audioengine sound and quality but without our built-in amplifiers. Beautiful, small, and affordable, AP4 is the perfect choice for your living room, bedroom or office and an ideal surround speaker for use with other Audioengine speakers in your home theater or stereo system.