Sennheiser HME 43-K Instructions For Use Manual page 12

Headphones
Transducer principle
Frequency response
Sound pressure level
Ear coupling
THD
Contact pressure
Nominal impedance
Size of earcups
Microphone
Transducer principle
Frequency response
Output voltage
Supply voltage
Current consumption
8
dynamic
200 Hz to 6,000 Hz
89 dB SPL at 1 V/1 kHz
supra-aural, closed
< 1 %
approx. 1.5 N
300 Ω
∅
51 mm
pre-polarized condenser,
noise compensating
400 Hz to 4,500 Hz
170 mV/Pa; adjustable from
40 to 500 mV/Pa
8 to 16 V DC
typ. 10 mA at 8 V