A solution has been found for the acoustic power extracted from the near potential field of a subsonic rotor, by interaction with a nonuniform inlet flow. The analysis is based on Lighthill's aerodynamic sound equation, modified to allow for a uniform mean flow, and is restricted to low‐solidity rotors (lifting line approximation). Within this approximation, the power at blade‐passing frequency is compared with that radiated from unsteady blade forces arising from the same nonuniform inlet flow. The comparison shows that more power may be radiated by the potential field interaction at high subsonic Math numbers, if the rotor disk loading is high.