With the aim to comply with the manufacturer's requirements for not overloading the tweeter at the low frequency part of frequency response the 315mm THD measurements were carried out at the next filtering conditions:
- at voltage levels 1 - 1.41 Volt - with High Pass Filter "on" (2nd order Butterworth type, 1000 Hz cutoff, HPF2-1000)
- at voltage level 2 Volt - with High Pass Filter "on" (4th order Butterworth type, 1000 Hz cutoff, HPF4-1000)
- at voltage level 2.83 - 5.6 Volt - with High Pass Filter "on" (4th order Butterworth type, 2000 Hz cutoff, HPF4-2000)