Hi, I haven’t got any experience of using the acoular packages but they look interesting!
However, unless you understand how the algorithms are actually working you will have problems fully implementing and seeing where you’ve gone wrong. I suggest Matlab / Simulink if you are familiar with this? A simple delay sum / filter sum beamforming process shouldn’t be too difficult to accomplish.
While summing the signals together (as with the output of mic 8) does indeed produce a beamforming effect, in terms of a circular array this has little use for direction of arrival (DOA) estimation as there is no clear overall lobes in the spatial spectrum as seen below in the beamforming response for the Matrix Creator dimensions. Sorry I didn’t label the axis!! 0-400 is the azimuthal angle (i.e. over 360 degs), 0-10k is the frequency (i.e. calculated for a Nyquist frequency of 8kHz, given the 16kHz sampling freq) and 0-100 the dB level.
Even if this method were used for a linear array, where a major lobe would generally be formed (frequency and mic element distance dependent) the direction of the lobe would need to be ‘steered’ by at least delaying the individual signals before summation.
Hope this help!