The HD measurements at distance 315 mm and voltage levels 2.83 - 8 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 level 11.2 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 80 Hz cutoff, HPF2-80)
The HD measurements at distance 315 mm and voltage level 16 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 120 Hz cutoff, HPF2-120)
The HD measurements at distance 20 mm and voltage 8 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 40 Hz cutoff, HPF2-40)
Before taking the measurements the speaker had been very good boken-in