The effects of a fluidic control on the aeroacoustic characteristics of a Mach 0.9 high-Reynolds axisymmetric jet are investigated experimentally. The air-microjet system comprised up to 36 impacting microjets directed towards the jet centerline, and was designed to allow the modification of various geometrical and aeraulical microjet parameters. A significant noise reduction was obtained for the entire range of theta, the angle theta designating the direction of noise emission. The dependency of the noise reduction with respect to parameters of the microjets system was studied and three parameters were mainly considered: the outgoing mass flux per microjet, the number of microjets and their layout in the azimuth of the main jet. Depending on the microinjection flow parameters, the global jet-noise reduction varied from 0 to 1.8 dB, showing some non-monotonic behaviors due to the change between subsonic and supersonic regimes of the microjets. For low values of number of microjets, the microjets seem to act independently, which was confirmed by aerodynamic studies by Stereoscopic Particle Image Velocimetry. These studies indicated a strong correlation between the maximum level of turbulence just behind the nozzle exit and the high-frequency noise, previously shown to potentially balance the acoustic benefits obtained for lower frequencies. The maximum level of turbulence measured at the longitudinal position corresponding to half the potential core length was shown to be also highly correlated to the jet noise reduction.