In the present paper a Steklov-Poincaré formulation is presented to solve the inverse problem of acoustic source reconstruction in confined domain [J. Acoust. Soc. Am. 130 (4), October 2011, 2016-2023]. The solution is obtained by the resolution of the Helmholtz equation applied on an empty bounded domain; the boundary is the union of the measurement surface and the surface of the vibrating structure. The difference between classical methods and the Data Completion Method (DCM) is that Cauchy datum (acoustic pressure and velocity) have to be known on the measurement surface to recovering data on the whole boundary. The DCM allows one to solve the inverse problem with acoustic perturbations due to sources on the exterior domain, or due to measurements in a confined domain, without altering the results. Experimental results are presented.