A wind power installation with - a tower, - an aerodynamic rotor, wherein the aerodynamic rotor - can be operated with a variable rotor speed (n) and - has a number of rotor blades respectively with an adjustable rotor blade angle (α), - a generator (Gen) for generating an electrical output power, wherein - for operating the wind power installation an operating characteristic (200, 202, 204, 300, 302, 304, 306), which indicates a relationship between the rotor speed (n) and the output power, is specified and - a controller, which sets the output power in a way corresponding to the operating characteristic (200, 202, 204, 300, 302, 304, 306) in dependence on the rotor speed (n), is provided, wherein - selectable as the operating characteristic (200, 202, 204, 300, 302, 304, 306) is a reduced-tonality operating characteristic (202, 204, 302, 304, 306), which is designed such that an excitation of a system resonance of the wind power installation is reduced as compared with an optimum-power operating characteristic (200, 300), without however excluding a speed that excites this system resonance and characterized in that - it is provided with a pitch control, which sets the rotor blade angle (α) in dependence on the generated output power in partial-load operation in a way corresponding to a pitch characteristic (700, 702, 800, 806), and wherein the pitch characteristic (700, 702, 800, 806) is adapted in dependence on the selected operating characteristic (200, 202, 204, 300, 302, 304, 306), in particular is selectable from a number of pitch characteristics (700, 702, 800, 806), in particular a dedicated pitch characteristic is provided for each operating characteristic. - a tower, - an aerodynamic rotor, wherein the aerodynamic rotor - can be operated with a variable rotor speed (n) and - has a number of rotor blades respectively with an adjustable rotor blade angle (α), - a generator (Gen) for generating an electrical output power, - for operating the wind power installation an operating characteristic (200, 202, 204, 300, 302, 304, 306), which indicates a relationship between the rotor speed (n) and the output power, is specified and - a controller, which sets the output power in a way corresponding to the operating characteristic (200, 202, 204, 300, 302, 304, 306) in dependence on the rotor speed (n), is provided, wherein - selectable as the operating characteristic (200, 202, 204, 300, 302, 304, 306) is a reduced-tonality operating characteristic (202, 204, 302, 304, 306), which is designed such that an excitation of a system resonance of the wind power installation is reduced as compared with an optimum-power operating characteristic (200, 300), without however excluding a speed that excites this system resonance and characterized in that - it is provided with a pitch control, which sets the rotor blade angle (α) in dependence on the generated output power in partial-load operation in a way corresponding to a pitch characteristic (700, 702, 800, 806), and wherein the pitch characteristic (700, 702, 800, 806) is adapted in dependence on the selected operating characteristic (200, 202, 204, 300, 302, 304, 306), in particular is selectable from a number of pitch characteristics (700, 702, 800, 806), in particular a dedicated pitch characteristic is provided for each operating characteristic.