Lightspeed mic gain

I recently purchased 2 sets of Lightspeed 20-3G headsets and handed down our
20xl's to my son and daughter.

Last weekend was our first trip with wearing the 20-3Gs. With the radios,
intercom and headset volume levels all set at a comfortable conversation
level, the takeoffs turned out to be absolutely deafening. The reverb from
the props and/or feedback through the mic or ANR was much much louder than
the older 20xls. Conversation would have been totally impossible during the
take off roll. My wife said that they didn't get any better even when she
pressed the ear cups to her head with her hands. Once the props were pulled
back to 2400rpms, everything returned to a comfortable level.

A recent thread about mic gain got me wondering if that might be the cause
of our problem. Has anybody had a similar experience?

Thanks,
Jim

Are you sure the noise came through the microphones? I've had loud
experiences with my lightspeeds when I didn't get a good seal from the ear
cups.

You might repeat the experiment with the squelch turned all the way up -
i.e. to where it squelches virtually everything. If the sound level is
reasonable, that would confirm a mic noise problem.

Alternately, if it is still loud, you have a noise cancelling problem.

KB

"Jim Burns" wrote in message
...
I recently purchased 2 sets of Lightspeed 20-3G headsets and handed down
our
20xl's to my son and daughter.

Last weekend was our first trip with wearing the 20-3Gs. With the radios,
intercom and headset volume levels all set at a comfortable conversation
level, the takeoffs turned out to be absolutely deafening. The reverb
from
the props and/or feedback through the mic or ANR was much much louder than
the older 20xls. Conversation would have been totally impossible during
the
take off roll. My wife said that they didn't get any better even when she
pressed the ear cups to her head with her hands. Once the props were
pulled
back to 2400rpms, everything returned to a comfortable level.

A recent thread about mic gain got me wondering if that might be the cause
of our problem. Has anybody had a similar experience?

Thanks,
Jim

Jim,

Hmm. This sounds weird. Is the noise coming from the engine or is the
headset "making" the noise through some electronic feedback in the ANR
circuitry? The latter would be unusual, especially if it happened in
both headsets the same way at the same time.

So you suspect a mic is coming open during take-off? My first thought
would be to adjust the intercom squelch setting, which is sensitive to
background noise and has to be adjusted accordingly. What intercom do
you use? Are you sure the noise is coming through the headset mics? If
so, by simply pulling the mic plugs, you can find out which headset is
the offender.


--
Thomas Borchert (EDDH)

On 2006-12-27, Jim Burns wrote:

Last weekend was our first trip with wearing the 20-3Gs.

Did you make sure the swivel mics were turned with the "talk" side
pointing toward you?

I have had the ANR-induced noise problem, but it's usually when I twist
my head and break the seal and let ambient noise in which is then badly
handled by the ANR.

--
Ben Jackson AD7GD

http://www.ben.com/

Thanks guys,
Mics were turned towards our mouths, I checked that when I put them in the
plane. I'm thinking mic noise because my wife pressed her ear cups tightly
to her ears trying to deaden the noise and she said it didn't work, plus the
noise seemed to be amplified. Next step will be to adjust the squelch on
the intercom. I didn't think of this as we had never had to touch it with
the 20xl's.

I don't think that it's an ANR problem as everything calmed down once we
pulled the props back and I remember turning mine off then back on and
noticing the difference. I'm thinking squelch more and more. Normally I
have it turned all the way down because our kids and my wife tend to leave
their mics well away from their lips, so the intercom kicks in at the
slightest whisper.
Thanks

Jim

Jim,

because our kids and my wife tend to leave
their mics well away from their lips,


That will mess up any intercom system. Training is needed ;-)

What model/brand of intercom is it?

--
Thomas Borchert (EDDH)

Instruction has been given... over and over and over.... training has not
occurred
Sigtronics 4 place intercom.

Jim

"Thomas Borchert" wrote in message
...
Jim,

because our kids and my wife tend to leave
their mics well away from their lips,


That will mess up any intercom system. Training is needed ;-)

What model/brand of intercom is it?

--
Thomas Borchert (EDDH)