A digitally controlled two dimensional loudspeaker array

Results

• Precise and smooth, “click” free sound moving

• Appreciable Doppler effect

• “Objective” sound scene

• Good distance perception

• 22 dB decay at medium frequencies between the center and a peripheral point 5 m distant (center of one shell) . Tested with filtered pink noise.

• Very sensible increasing of the active insulation with people beneath the array

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13/02/2008


	Now the scheme of the processing system which should drive the array. It is still to be implemented, but the idea is to use a linux platform with the Anders torger brutefir running on it. The systems should have 5 -10 inputs, each related to one of the virual source (focus) we want to create. The outputs ars 96 as I told before. This is a matrix of proces which provides for positioning of the vistual source, whilst other filter are put just in the output or in the input.
	In particular: the input FIR should be 2048 long, and shoul provide for the WFS filter, the gain increasing with frequency, and for speaker equalization. This two filter have shape which are roughly opposite so it is good to put them toghether for the preservation of the dynamic of the system. More: the total filter will problably be empiric, that is an inverse filter of the focus response in the focus when all the other filter are already set.
	The matrix filter, which provides for spatialization, contain the dynamic gain and delay necessary for focalization, and to the anti-alisaing sampling filter.
	The output FIRs, one for each out channel, provides for speaker phase matching, i think that 64 taps are enough for it.