DI 5.5BPS 5.25” Bipolar In-Wall / In-Ceiling Speaker. More Range Than. Speakers Twice Its Size. Powerful far beyond its diminutive size, the DI 5.5BPS delivers captivating surround sound with the bass output and dynamic range of traditional 8" speakers. Hidden within your walls or ceiling, its lifelike sonic performance and broad, even dispersion become even more impressive. While other in-wall speakers fall short in sound quality and stealth, the DI 5.5BPS sets an impossibly high standard.