Actually that "loud, monotonous racket" the ANR is designed to eliminate
comes mostly from the engine, so I usually don't turn on my ANR until after the
runup.

No, the loud monotonous racket is, well, noise. It's too loud and
conglomerated for the healthy human ear to pick out individual sounds.
If you want to hear what the engine is really doing, in great detail,
turn your ANR headset *on*.

I'm always amazed at the little things I can hear with them on -- heck,
I can hear my kids talking to each other in the back seat -- that I
miss if I forget to turn them on.

For example, my engine makes a tell-tale whining noise right after
start-up that I can only hear with the ANRs on. It slowly builds in
pitch until it disappears, usually within a minute or two after start
up. I've guessed the alternator, since it's the only belt-driven
accessory, but I'm not sure.

I've asked my A&P to figure out what it is (it's made the noise since
the engine came out of the overhaul shop -- and probably before that),
but he can't hear it. Neither can I, without the ANR headsets that he
refuses to use.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"