> The dual blower is completely non-standard, as well. Goldberg says that the engineering team found that by splitting each impeller of the blower by a divider partway up its height, they were able to make adjustments using the disc that allowed for different pitches of the blades above and below the divider.
“That results in drawing different amounts of airflow from each section of the box so we can tune for the thermal performance based on the cooling needs, adjust the height of that divider, adjust the the pitch of the blades and each section and then kind of optimize for thermals and acoustics at the same time,” says Goldberg.
https://techcrunch.com/2022/03/17/apple-execs-on-developing-...