The HD measurements at distance 315 mm and voltages 2.83 - 22 Volt were carried out with digital High Pass Filter (2nd order Butterworth type, 50 Hz cutoff, HPF2-50)
The HD measurements at distance 205 mm and voltage 16 Volts were carried out with digital High Pass Filter (2nd order Butterworth type, 20 Hz cutoff, HPF2-20)
Before taking the measurements the speaker had been very good broken-in
The detailed review of the WO24TX-8 speaker