The HD measurements at distance 315 mm and voltage levels 1 - 11.2 Volt were carried out with digital High Pass Filter (2nd order Butterworth type, 800 Hz cutoff, HPF2-800)
The voice coil current HD measurements were carried out with digital High Pass Filter (2nd order Butterworth type, 800 Hz cutoff, HPF2-800)
The detailed review of the T34S-4 speaker