Leading eVTOL companies claim that their aircraft can be 10, 100, or even 1000 times quieter than conventional helicopters. Are such low noise levels possible in theory? And what progress has been demonstrated so far? To answer these questions, this video reviews the principles of sound waves and aircraft noise. Using this knowledge as a foundation, various noise reduction technologies, in particular, patents by Joby Aviation, are reviewed. Finally, the noise claims by leading eVTOL companies are assessed.