I'm a new Spark pilot (first post) and I have to say that the only part of flying I haven't enjoyed is the 'wasp' buzz. I live in a remote, quiet area which makes it more audible. My son's Mavic Air can be heard close to Km. away from launch... so I jumped at the Master Airscrew props when I learned of them. I just took delivery 30 minutes ago and of course dropped everything to try and compare them. I did a take-off and hover at 2 M. with the DJI foldies on and used the Decibel Meter Pro on an iPhone 6 to measure sound. With the microphone aimed at, and 2 M. away from the Spark the reading was 72-84 dB. Landed, quickly changed props and repeated. M.A.S. props were 63-72 dB under exactly the same conditions. So, somewhere around 10-12 dB drop in my case but more importantly, as mentioned by others, the pitch is lower and less annoying. I haven't the time today to test out performance claims for longer flights and smoother maneuvering but I'm already happy so anything else will be a bonus. Stay tuned...