Purifi PTT6.5X04-NAA-08A

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

The voice coil current HD measurements were carried out with High Pass Filter "on" (2nd order Butterworth type, 50 Hz cutoff, HPF2-50)

Before taking the measurements the speaker had been very good broken-in

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