  This paper presents an alternative energy function for Global Optimization
(GO) beamforming, tailored to acoustic broadband sources. Given, that
properties such as the source location, multipole rotation, or flow conditions
are parameterized over the frequency, a CSM-fitting can be performed for all
frequencies at once. A numerical analysis shows that the nonlinear energy
function for the standard GO problem is equivalent to the source's Point Spread
Function (PSF) and contains local minima at the grating- and side lobes'
locations. The energy function is improved with the proposed broadband energy,
as it averages the PSF. Further, it simplifies the process of identifying
sources and reconstructing their spectra from the results. The paper shows that
the method is superior on synthetic monopoles compared to standard GO and
CLEAN-SC. For real-world data the results of the proposed method and CLEAN-SC
are similar, and outperform standard GO. The main difference is that source
assumption violations cause noisy maps for CLEAN-SC and cause wrong spectral
estimations of the proposed method. By using reasonable initial values, the GO
problem reduces to a Local Optimization problem with similar results. Further,
the proposed method is able to identify synthetic multipoles with different
pole amplitudes and unknown pole rotations.
