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Headset Issue

Old 5th Aug 2019, 20:10
  #1 (permalink)  
Thread Starter
Join Date: Aug 2019
Location: Wales
Posts: 1
Headset Issue

Hi all,

Firstly, apologies if this is not the correct place to post this question.

I have a Sennheiser HME100 headset. Recently it appears to have developed an issue where the mic is transmitting the ambient sound of the cockpit back to myself and passengers. In some aircraft, the noise is constant and in others the noise is on and off. It is rather annoying and such a distraction. Apart from this, the headset works great.

The issue is only internal, the PTT works as normal.

My question is, is there something on the headset that could be causing the issue? Does the mic need a certain volume to "activate"?

Your help is greatly appreciated.

kind regards,

Chris2591 is offline  
Old 6th Aug 2019, 00:00
  #2 (permalink)  
Join Date: Jul 2008
Location: Skating away on the thin ice of a new day.
Posts: 1,022
Sounds like it has a VOX (Voice operated transmit) or open mic happening. VOX operated mics will work if there is sufficient background noise. I'm not familiar with the model. Is there a VOX feature?

In a quiet cockpit I assume there is no unwanted audio being transmitted, but it will transmit if there is louder background noise?

Tried it in other aircraft? Another headset in the one you are flying?
ampclamp is offline  
Old 6th Aug 2019, 03:00
  #3 (permalink)  
Join Date: Nov 1999
Location: UK
Posts: 1,131
Do you use a microphone windshield? (a foam cover)

Many pilots do not, so as well as being difficult to be understood by ATC owing to audio distortion caused by plosive sounds, the microphone gradually fills up with crud. Aviation microphones have a passive noise cancelling feature which reduces cockpit background noise from the mic - as long as the mic is clean internally, has a windshield and is placed very close to your mouth. If crud builds up inside the mic, the noise cancelling feature stops working and your mic puts more and more background noise on your transmissions, which sound noisier and noisier.

This noise might be what is triggering the VOX of your intercom, (if fitted). If so, there might be an adjustment control of the VOX switching threshold on the intercom unit.
Uplinker is offline  
Old 6th Aug 2019, 10:38
  #4 (permalink)  
Join Date: Nov 2015
Location: BRS/GVA
Posts: 295
Noise cancelling mics have 2 microphones, one which picks up the ambient sound another your voice, and it subtracts one from the other. It could be its faulty and the wrong mic is feeding through, but i've also seen models where the ambient mic is on the back of the boom, if you have it rotated the wrong way voila.
hoss183 is offline  

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