No, it is not true that Ducati has patented the sound produced by their Desmodromic (Desmo) engine. While Ducati motorcycles, particularly those equipped with Desmo engines, are known for their distinct and iconic sound, there is no official patent on the sound itself.
Patents are typically granted for inventions or technical innovations, and they provide exclusive rights to the patent holder for a specific invention or process. Sounds, including the sound produced by an engine, are generally not eligible for patent protection.
The sound of a motorcycle engine is a result of various factors, including engine design, exhaust system configuration, intake system design, and other components. Motorcycle manufacturers often emphasize the unique characteristics and sound of their engines as part of their brand identity and marketing efforts. While Ducati's Desmo engines have a distinctive sound, it is not a patented feature.