The THD measurements at distance of 20 mm and voltage levels of 4 - 5.6 Volt were carried out with High Pass Filter "on" (4th order Buttreworth type, 20 Hz cutoff, HPF4-20).
The THD measurements at distance of 315 mm and voltage levels from 2.83 to 5.6 Volt were carried out with High Pass Filter "on" (2nd order Buttreworth type, 50 Hz cutoff, HPF2-50).
The THD measurements at distance of 315 mm and voltage levels from 8 to 16 Volt were carried out with High Pass Filter "on" (2nd order Buttreworth type, 80 Hz cutoff, HPF2-80).
The speaker before the measurements had not been broken in.