The playback SPL values are just slightly larger than the measured values during the boat pass-by, the playback error in terms of wideband SPL was just 3.5 dB for FB and 2.1 dB for TF. On the other hand, the calculated values of particle acceleration generated by the loudspeaker are much larger than those which were present during the recording of real boats. In this case the error, in terms of wideband particle acceleration level, was calculated to be respectively 10.2 dB for FB and 3.8 dB for TF. The spectra (Fig. 4) clearly shows that the acceleration level in the near field boosts significantly at very low frequency and the calculated values of La (particle acceleration level)