  It is shown that the use of the equivalent source method allows one to
reconstruct the sound field excited by an acoustic radiator in free space from
the measurements of the sound filed excited by this radiator in a tank with
reflecting boundaries. The key assumption underlying the proposed approach is
that the same set of monopoles with the same strengths can reproduce the field
of the radiator both in free space and in the tank. The monopole strengths are
reconstructed from the measurements in the tank, and the field in free space is
then calculated using the known Green function. The feasibility of the approach
is demonstrated in a tank experiment.
