Here is a video from last year Monza race.

In the video you can hear the sound generated by the blown diffuser when drivers brake for the corners. This system has clearly given the advantage to the Red Bull F1 team and as you can hear both cars have a heavier sound than others while braking. This is a complex system that allows the driver to use the exhaust to blow the diffuser while braking, thus generating the much needed down force in these type of cars to have a better performance. The system was rejected by several teams but at the end the FIA decided that it was a legal system, therefore, all the teams (or at least the top ones) had to adjust and quickly develop their cars to work with the system as well.