Purifi PTT8.0X04-NAB-02

The HD measurements at distance 315 mm and voltages of 2.83 - 11.2 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 of 16 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 80 Hz cutoff, HPF2-80)

The HD measurements at distance 20 mm and voltage of 11.2 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 20 Hz cutoff, HPF2-20)

The voice coil current HD measurements at voltages 2.83 - 8 Volt were carried out with High Pass Filter "on" (2nd order Butterworth type, 20 Hz cutoff, HPF2-20)

Before taking the measurements the speaker had been broken-in with sinusoidal voltage of 9 volts (26 Hz) for 60 minutes

The detailed review of this midwoofer - https://hificompass.com/en/reviews/purifi-ptt65x04-naa-08-65-alu-midwoofer