Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Transmit noise

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

ianxbrown

Joined: 16 May 2009
Posts: 80

Posted: Sun Aug 30, 2009 6:50 am Post subject: Transmit noise

I'd like to offer two small ideas since they both seem to make a big difference in my aircraft:

 

 1.  The headset manufacturer says put the mike 1/8" from your mouth.  That's pretty close, and the further away it is the more other noises can be heard.

 2.  I noticed most of my transmit noise went away if I unplugged the second headset, or switched the intercom to "isolate" even though the second PTT wasn't pushed.   Not sure why that is, or whether it was just noise in my headset that wasn't actually being transmitted.

 

 Ian Brown

 Bromont

 Quebec, RV-9A

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

nuckolls.bob(at)aeroelect
Guest

Posted: Sun Aug 30, 2009 8:19 am Post subject: Transmit noise

At 09:45 AM 8/30/2009, you wrote:

 	  Quote: 	
		  I'd like to offer two small ideas since they both seem to make a big 

difference in my aircraft:



1.  The headset manufacturer says put the mike 1/8" from your 

mouth.  That's pretty close, and the further away it is the more 

other noises can be heard.


	


    Sure. This is typical of any noise canceling mic.

    The term noise cancelling is mis-leading. Microphones

    cannot differentiate between "noise" and "good stuff."

    Depending on their quality, they may do a fair job of

    differentiating between near-field sounds (your voice)

    and far-field sounds (noise). The further your voice

    moves away from the microphone, the less it looks like

    good stuff and the more it looks like noise.



 	  Quote: 	
		  2.  I noticed most of my transmit noise went away if I unplugged the 

second headset, or switched the intercom to "isolate" even though 

the second PTT wasn't pushed.   Not sure why that is, or whether it 

was just noise in my headset that wasn't actually being transmitted.


	


    Aha!  TWO microphones that are tied together without

    benefit of separate voice-operated switching. These

    systems suffer full-time bombardment of TWICE the

    noise when only one person is talking. This

    causes you to tighten squelch controls to silence the

    extra noise and requires that voices be louder (or

    microphone half way down your throat) in order that

    the tighter squelch be accommodated.



    I'm pretty sure that 90% of your problem arises from

    the combination of headsets and your audio system's

    handling of microphone signals. It is unlikely that

    you can achieve much better results without replacing

    the intercom, headsets or both.



    You're not alone in believing that stuff designed

    for "aircraft" is suited for cockpits with essentially

    open-air noise levels. I'm thinking that intercoms

    designed for mounting in helmets of motor cycles may

    be better designed for this task.

        Bob . . .



         ---------------------------------------

        ( . . .  a long habit of not thinking   )

        ( a thing wrong, gives it a superficial )

        ( appearance of being right . . .       )

        (                                       )

        (                  -Thomas Paine 1776-  )

         ---------------------------------------

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum