Grain loss in a combine is usually measured after the fact, by impact sensors on the sieves or by a human walking behind the machine counting kernels on the ground. Northrake's new HR9 tries to catch it earlier, by listening to the threshing drum itself.
Two microphones sit in the concave housing, isolated from frame vibration. Cracked kernels and over-threshed straw produce a different acoustic signature than clean separation, and the controller uses that to nudge rotor speed and concave clearance continuously rather than waiting for grain to reach the loss monitors several metres downstream.
Worth between a half and one point
Northrake claims the system reduces total loss by 0.4 to 1.1 percentage points depending on crop and moisture, with the largest gains in soybeans harvested dry, where cracking is easiest to cause and hardest to see from the cab.
The feature is standard on the HR9 and will be offered as a retrofit kit for the previous HR8 from the second half of 2027, subject to a controller software update that dealers can flash in roughly two hours.