The HD measurements at distance of 315 mm and voltage levels 2 - 2.83 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 50 Hz cutoff, HPF2-50)
The HD measurements at distance of 315 mm and voltage levels 4 - 11.2 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 80 Hz cutoff, HPF2-80)
The speaker before the measurements had been good broken-in