Stefan Mileschin

A stepped inlet is used on the fan body to promote turbulent airflow into the fan, which improves compression of the airstream and reduce the noise signature. Small inner microstructures also help to improve airflow and static pressure efficiency on the suction side of the Heptaperf fan and reduce the fan noise. The improved airflow stream is pushed through the "Focused Flow" frame, where it is straightened, channeled, and "Focused" by the 11 stator vanes. These vanes are equipped with Vortex control notches and are placed at variable intervals that range from 31 to 37 degrees apart; all in the name of improved flow and reduced noise. The second generation SSO2 full metal bearing is machined from solid brass for a longer lifespan and improved fan blade stabilization. The motor magnet is placed closer to the axis of the fan blade shaft; again, for improved stabilization in combination with the new metal shell. The NF-F12 PWM has removable rubber vibration dampers to keep vibrations quiet. The back side of the motor houses the new NE-FD1 PWM IC, which incorporates SCD technology to reduce noise at very low fan speeds, as the NF-F12 PWM can run as low as 300 RPM.

http://www.overclockersclub.com/revi...ua_nf_f12_pwm/