On measuring loudspeakers:
a] As 'SIY' (aka SY) wrote: It's easy to test transducers- what's harder is interpreting the measurements.
b] One needs to read the sections of the new Floyd Toole book on measurements.
c] In room measurements have many limitations.
d] Even anechoic chamber measurements on a horizontal and vertical turntable have limitations.
e] Testing at 1/20 octave and many rotation angles while return a huge data file, which is subject to a great deal of interpretation.