How to avoid the Fan noise? Hollyland Tech November 30, 2020 07:16 Updated The Fan Speed of the MARS 400S is unable to adjust. However, this noise will be recorded in the video in some quiet cases under careless operations. Below is the right way to avoid this noise: Keep the dissipation holes of the MARS 400S away from the camera's mic or the external mic you are using. Related articles Can we use mushroom antenna on the MARS 400S ? UPGRADE Did the DC adapter charge for batteries ? What is the specifications of DC adaptor? How to connect a mobile device to the HollyView App ? Comments 0 comments Article is closed for comments.