Our choice: single transducer,
extended range
InAxisSpectrum polarVsFreq OctPolars
13/02/2008
So at the end our choice fell on what was maybe the simples solution one could ever imagine, even without all the discussion made so far. A single diver extended range, which provides for an acceptable coverage of the area and of the frequency spectrum as well. I measured the directivitivity of the speaker, already inserted in the array, and these are the result:
in axis tranfer function: it is not flat, but it radiates sufficiently high at frequencies up to 10-15 KHz. With so many speaker and FIR filtering I think we can reach a transfer function in the focus that is more than flat.
Here we have emission angle vs frequency, and here the polar pattern in octaves, you can see it as section of this surface plot.
This is the curve that describe the reconstruction condition antialiasing. In theory we shoul have yellow inside this “funnel” and blue outside. This doesn’t happens, we have also lobes here.. But there is a general matching which makes us optimistic.