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