Delay-and-sum is one of the most fundamental signal processing techniques to estimate the direction of a sound source based on measurements from an array of microphones. However, the estimation of distance and/or sound pressure level of the source cannot be accurately retrieved if we do not take into account the properties of the acoustic environment, the sound field, where the measurements take place. In this contribution, we show the performance of a delay-and-sum beamformer in the spatial localisation of a source emitting a sound of constant overall level. The source is gradually moved in an area of 230 m2 with source-receiver distances up to ∼35 m. Results are shown before and after applying a level correction based on the inverse distance law and a transfer function estimate obtained empirically. This transfer function represents a pragmatic simplification for the acoustic environment, which otherwise can be complex to measure due to the more or less influence of absorption, reflection, diffraction, refraction, and diffusion phenomena. Our evaluation is focused on the estimated source location obtained from the maxima of the imaging results and on the estimated sound pressure levels.