Lightspeed Headset mic noise cancelling performance

I tried my Lightspeed QFR-XCc's out today in a 152 Aerobat...first
time.
My CFI noticed I had a lot of cockpit noise on my voice during
intercom action. It was like the mic gain was too high.

Has anyone else noticed this kind of problem? It's like the
noise cancelling mic wasn't cancelling the cockpit noise
as well as it should.

Could this be a mic gain problem?

-Thanks,
CT

CharlieBuda wrote:
I tried my Lightspeed QFR-XCc's out today in a 152 Aerobat...first
time.
My CFI noticed I had a lot of cockpit noise on my voice during
intercom action. It was like the mic gain was too high.
/snip/

Charlie,

I have no experience with the Lightspeeds, but a couple of things are
worth checking out. There may be a gain adjustment on the mic. If so,
a local avionics shop should be able to adjust it properly, or you can,
with an appropriate small screwdriver. But first, make sure you're
speaking into the correct side of the mic. It could be turned
backwards, in which case you are speaking into the "noise cancelling"
side, and the cockpit noise is going into the "voice" side.

Happy Flying!
Scott Skylane

Scott,

The correct side of the mic is labelled "TALK" and I did find a small
gain pot located on the back side of the mic. I hooked up a 470 ohm
resistor to +12V and put the mic on my oscillocope. At full gain the
mic was putting out 3 volts peak-to-peak! I cranked the gain down to
1v peak-to-peak which is more nearly the standard for aviation
microphones.

So next time I fly I will try it again....next week if the weather
holds.

Thanks,
Charlie


Scott Skylane wrote:
CharlieBuda wrote:
I tried my Lightspeed QFR-XCc's out today in a 152 Aerobat...first
time.
My CFI noticed I had a lot of cockpit noise on my voice during
intercom action. It was like the mic gain was too high.
/snip/

Charlie,

I have no experience with the Lightspeeds, but a couple of things are
worth checking out. There may be a gain adjustment on the mic. If so,
a local avionics shop should be able to adjust it properly, or you can,
with an appropriate small screwdriver. But first, make sure you're
speaking into the correct side of the mic. It could be turned
backwards, in which case you are speaking into the "noise cancelling"
side, and the cockpit noise is going into the "voice" side.

Happy Flying!
Scott Skylane