Thank you all for your help and input. Art thank you for the time and detailed info!
John,
Though you were only considering a pair of BC215, or four TH118XL, thinking about Ivan Beaver’s writing he had measured -10dB at 90 degree off axis around 40-50 Hz with Bdeap cabinets in a 2 over 2 configuration with the "mouths" in a cloverleaf pattern, thought it would be interesting modeling four BC215 configured like that in Danley Direct (DD).
In post #4, Ivan explained that the DD models are based on
“actual measurements of the different configurations (1,2 4) as measured outside on the ground without reflections. They are not simulated.”The BC215 in DD has interesting anomalies.
The BC215 has a 45 x 45 inch boundary with a small mouth exit in one corner, an asymmetrical cabinet, yet as a single cabinet DD plots it as axisymmetric, left/right being a mirror image with a “pointy” lobe directly in front.
No doubt DD is based on actual measurements, but forward symmetry for an asymmetrical cabinet can’t be valid.
When four BC215 are arrayed in a symmetrical “cloverleaf”, mouths at the four corners, the axisymmetric array’s pattern becomes asymmetrical in DD, a kind of “pinwheel” pattern.
The attached DD models are a 100 x 100 meter area, with 3dB per color change.
The models show a distorted directivity effect, but ignoring the anomalies, demonstrate that four BC215 arrayed in a “cloverleaf” do show directivity similar to what Ivan reported for the Bdeap cabinets 16 years ago.
Unlike Ivan, I never even broke a sweat stacking or flying those 360 pound cabinets!
Art
