Beamforming is an excellent approach to acquire the acoustic signature of rooms and buildings, superimposing acoustic images on 3D models to create informative 3D acoustic maps. These measurements give information on various factors such as sound propagation, reflective and absorptive surfaces, leakages, sound bridges, reverberation time and many more. While simulations serve to merely predict the acoustic behavior of performance spaces, measurements at the real site allow for verification of these simulations by acquiring the true acoustic signature of these spaces. Such on-site measurements have been carried out at the Michigan Stadium, US as well as the Coliseum and the Ancient Ostia in Rome, Italy. This practical paper aims to present measurements carried out on theatres and stadiums and the results thereof showing the applicability of beamforming systems to this end.