Wayne Parham Messages: 18786 Registered: January 2001
Illuminati (33rd Degree)
Measure at least 2M away and look for response that looks like the curve published by JBL. Best to lay the speaker on its back outdoors and suspend the microphone above it. Pay the most attention to the response above 500Hz, 'cause that's where you'll find the most variation from substandard recones.
Since we're looking mostly at HF, you can do a pseudo-anechoic measurement indoors, if you're familiar with gating. But if not, measure outdoors using the method I described above.