PR’s Data (old):

Fs = 29.65 Hz
Qms = 6.0900
Qes = 0.3560
Qts = 0.3363
Vas = 110.52 Liters
Cms = 6.314E-4 M/N
Re = 6.69 Ohms
BL = 12.64 N/A
Sd = 0.0353 Sq. Meters
Mms = 0.04563 Kg
Ref Efficiency = 0.778 %
Predicted Output = 91.11 dB/1W/1M
Predicted Sensitivity =  91.89 dB/2.83v/1M
Xmax = 4.14 mm