Founded in December 1982 by Bernhard Mörtl, ATL Lautsprecher GmbH Vertriebsgesellschaft emerged as a strong player in the audio equipment industry. The company initially acquired the inventory of Atlantic Lautsprecher GmbH, where Mörtl previously served as Sales Manager, and entered into a revenue-sharing collaboration with acoustic researcher Hans Deutsch. Known for its unique technical innovations, ATL's speakers often featured the "Hornresonator," a specialized form of the bass reflex principle. This unique technology allowed air mass at a narrow outlet to act as a membrane, whose vibrations were amplified by a short horn at the reflex opening. Coupled with this was the concept of an "acoustically active crossover," a set of mechanical filters and housing specifications designed to separate frequency ranges effectively. In 1989, after an initial dip in sales and a halt in new developments from Hans Deutsch, the company rebranded as ATL Elektro-Akustik Vertriebs GmbH, with Klaus Dotter stepping in as the Chief Developer. Dotter's influence led to a transition from the signature Hornresonator to a more conventional bass reflex principle and Scandinavian woofers with PP membranes. The speakers were categorized into a 700 series, with the high-end models known as the "Pro-Line," characterized by their premium finishes and beveled edges. Through the years, ATL introduced several other lines, including the design-oriented "Avantgarde" and the ultra-slim "Slim-Line" series, which stood out for its narrow front panel and side-mounted woofers. However, despite being Germany's fourth-largest speaker manufacturer at its peak, the company ceased operations in 1994. While ATL’s original journey concluded, the brand's legacy in innovation and quality remains a fascinating chapter in the history of audio engineering. The mark ATL left on the industry, from its unique Hornresonator to its collaboration with prominent figures like Hans Deutsch and Klaus Dotter, makes it an indelible part of audiophile lore.