[FullRangeMan]

A question about Line Array Comb Filter in a OB panel with two or three 15inches wideranges, 8ohms each, linked in parallel for 4 or 2,6ohms, driver spl is 95db as OB.
Wonder IF on a OB panel with only two or three 15inches woofers/midrange drivers I will get bad Comb Effect or other bad effect??
The space between the drivers holes is 13,5cm(5,25inches) the holes have 35cm/13,75inches diameter.
Center to center cone space is 49cm/19,25inches for two drivers and 115cm(45inches) for three drivers.
Thanks yours opinions,  Gustavo

[TerryO]

Gustavo,
Comb Filtering is a result of beaming. The larger the driver, the lower in frequency that comb filtering begins. The only way that you can avoid this is by using a focused array, but that is quite limited as to where you can have your listening position, etc.

Best Regards,
TerryO

[Danny Richie]

TerryO is kind of right in that comb filtering and beaming effect is one in the same when looking at a single source or multiple sources covering the same range.

The real issue is cancellation effects caused by a variation in distance from each source or from a given point on a single source.

When using multiple drivers that are point source drivers then you really need for the center to center spacing to be 1" or less to minimize the effect to just the top half of the top octave. or with a continuous voice coil diaphragm like a planar magnetic or ribbon device you need to get each playing surface to less than 1" apart.

Using sources that are as large as you are proposing will cause 6db peaks and 15db dips all over the place.

Center to center cone space is 49cm/19,25inches for two drivers

That would cause your cancellation effects down into the 700Hz range.

and 115cm(45inches) for three drivers.

That would cause cancellation effects down into the 300Hz range.

[FullRangeMan]

Thanks boys, for your valuable advices once more.
Gustavo