Acapella Audio Arts is a German luxury loudspeaker manufacturer founded in 1978 by Alfred Rudolph and Hermann Winters in Duisburg, Germany. The company is renowned as one of the oldest hi-fi manufacturers in Germany, specializing in ultra-high-end horn-loaded speakers with revolutionary plasma tweeter technology. Their signature products include massive spherical horn speakers that reproduce the entire audible spectrum without traditional membranes. The company's flagship model, the Sphäron Excalibur, stands over seven feet tall, weighs 2,728 pounds, and costs $455,000, establishing them as creators of some of the world's most expensive speakers. Currently undergoing generational transition, the founders are being succeeded by Alfred Rudolph's sons Robert and Richard, who have been involved in operations for over a decade. Each speaker is hand-built to order by skilled artisans in their Duisburg facility, combining cutting-edge acoustic technology with artistic design.