In rec.aviation.misc Newps wrote:
: About what you'd expect from a salesman who's company who is getting their
: ass kicked in the market. To put on an ANR headset in pretty much any spam
: can and then to say, apparently with a straight face, that just because it
: sounds quieter it really isn't is just assinine. I too have a pair of DC
: 13.4's. Absolutely no comparison. These pieces of crap will no doubt last
: my lifetime, because they never get used. Saying not to get ANR is like
: saying stick with Loran, GPS doesn't offer you much more.


Not necessarily B.S... The frequencies that are hearing-damaging are not
necessarily the same as those that are annoying. The Lightspeed K/XL/G series all
*depend* on ANR to reduce the perceived noise level. That's primarily the engine and
it's harmonics (low frequency from 70-250 Hz or so). These frequencies aren't as
hearing-damaging as the mid-frequencies. These headsets have extremely poor passive
performance, and thus very poor performance at approx 1kHz. Not only that, but an
unavoidable side-effect of ANR is spillover, which for the Lightspeeds is in about the
same range. I've seen independent reviews of them showing the K/XL/G headsets
*amplifying* noise in the 1khz frequency band.

For many planes with modest noise damping material, it's not a problem. My
Cherokee has no interior, so it has *lots* of mid-frequency rattle. I cannot use the
K/XL/G headsets because the mid-frequencies are painfully loud. (I'm also more
sensitive to these frequencies than most people). I did, however, purchase a
Lightspeed QFR XC2, since it's got very good passive, and mild active. I'm very
satisfied with it... doesn't cut out as much of the engine drone as the K/XL/G
versions, but the clamping is very low, and mid-frequency attenuation is much better.

In short, for most planes with some modest noise-proofing where the engine
is extra-loud, the Lightspeed K/XL/G headsets are great. Very comfortable and light.
They're plastic, so a bit fragile... especially in the cold. They have a very good
"wow-factor" at making the engine noise go away... that's how they sell a lot. For my
situation, however, they don't work at the sensitive mid-frequencies.

YMMV
-Cory

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