HMEC 45-KA / HMEC 45-CA
A headset comprises two units, a headphone and a microphone. The HMEC 45-
KA/-CA headset is mostly used for communication in aircraft cockpits.
왘
The microphone is a high quality back-electret condenser microphone. As per
TSO / ARINC it receives its operating voltage via a connector from the
aircraft´s internal power supply.
왘
The headphone is a Sennheiser
NoiseGard
®
system. This is a dynamic
headphone system which, in addition to reproducing the original audio signal,
electronically cancels the low frequencies of the ambient noise. This active
noise compensation operates on the principle that sound and „anti-sound“ (in
phase opposition) cancel each other out. The
NoiseGard
®
compensation
circuitry in the headphone requires an extra power supply, so a battery com-
partment has been integrated into the headset cable (see illustration on the right).
Clearly intelligible communication is ensured, and the pilot no longer has to
turn the volume up to overcome ambient noise.
NoiseGard
®
increases your comfort,
but it is no medical hearing protection!
Active noise compensation with NoiseGard
®
100
200
500
1000
5000
2000
Frequency / Hz
0
10
Attenuation in dB
Human speech
Warning Signal
20
Reduction of the
subjectively perceived
noise level with
Noisgard
Summary of Contents for HMEC 45-CA NoiseGard
Page 5: ...Adjusting the headband...
