The HD measurements at distance 315 mm and voltage levels 2.83 - 5.6 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 50 Hz cutoff, HPF2-50)
The HD measurements at distance 315 mm and voltage levels 8 - 16 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 80 Hz cutoff, HPF2-80)
The voice coil current HD measurements at voltage levels 2 - 5.6 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 50 Hz cutoff, HPF2-50)
Before taking the measurements the speaker had been very good boken-in