We have the capability to measure many different types of loudspeaker systems. Some are intended to be very directional, such as line arrays.
Others are intended to be omni-directional (no directivity control), such as a dodecahedron loudspeaker.
We can also measure using different techniques. Measuring each pass band (i.e. LF and HF) separately allows the crossover filters to applied to
the measured loudspeaker data in post processing. If the crossover filters are changes it is a simple matter to apply the new filters. There is no
need to remeasure the loudspeaker data, as it has not changed.