Ventilation strategies play an important role of enhancing energy conservation, Indoor Air Quality (IAQ) and acoustic comfort in any conditioned space. Impinging jets are used in such application and should be understood to be controlled. This paper focuses on the flow physics and the aero-acoustic coupling of an impinging jet ventilation system. Experimental data coupling are obtained thanks to simultaneous measurements of the velocity and the acoustic fields using respectively time-resolved particle image velocimetry (PIV) and a microphone. Spatio-temporal cross-correlations between the transverse velocity and the acoustic signals give us a better understanding of the self-sustained tones generated in impinging jets. A pre-whitening technique is used to investigate the coupling between the acoustic and the velocity signals. This method is useful for analysing small random signals superimposed on a high amplitude pure tone.