0.00 MANY_EXCLAMATIONS Subject has many exclamations
Paul:
Have you considered Communications Earplugs? Allow me to explain.
Your observations are on the mark. I did a spectral analysis of Europa
cockpit noise some time back and found that indeed it has a lot more
high frequency content than your typical Lycoming. This comes from
the gearbox and other mechanical noise; its suprising how much content
there is between 200-600Hz.
This is exactly the frequency range that ANR headsets can't cancel out
effectively. They're designed to remove noise frequencies below 200Hz.
The penalty for improved low frequency attenuation is reduced attenuation
in the 200-1000Hz range for two reasons:
1. peaking effects caused by delay in the cancellation signal;
2. reduced attenuation owing to the positioning of the ANR speakers
and the filling of the earcup with nonabsorptive electronics.
If you look at the attenuation curves of any ANR headset, you will see a
pronounced reduction in attenuation at these frequencies. The Telex ANR50D
supposedly has less than 10dB attenuation between 800-1000Hz, even though
its sub-200Hz performance is spectacular! (check out Quiet Technolgies'
website)
Karl's suggestion of the Lightspeed CrossCountry is probably the best solution
if you want an ANR headset. Lightspeed optimized that product for high
passive noise reduction and moderate ANR. Much better for Rotaxen.
Trouble is, not too many people fly behind Rotaxen, so their higher end
headsets sell much better.
However, the best solution is....earplugs!
Recently, several earplug-style headsets have come on the market.
They combine an earspeaker with a very effective earplug
to get attenuation numbers that are better than the best ANR headsets
at sub 200Hz (save the ANR50D) and absolutely stellar attenuation at
higher frequencies.
There are 3 competitors: The $500 Panther CAT, an in-mold earplug design
with a subvocal microphone;
The $365 QuietTechnologies AuriComm, an
expanding
foam model with an attached boom mike;
The $550 ClarityAloft, also an expanding
foam
model with
a boom mike supported by a
back-of-the-head
band.
The Panther CAT has been reviewed in Aviation Consumer. It has several
problems. The seal can be too easily broken by chewing, yawning;
cord microphonics; etc.
I've flown with the AuriComm. It's a good design, but the attached boom mike
may compromise the seal (they've just added a headband to address this).
The ClarityAloft is the most refined of the bunch. They've dealt effectively
with
cord microphonics and the need for earplug mechanical isolation.
I also like the ClarityAloft because of another reason...you can wear regular
ear
defenders over them. Belt and suspenders? Perhaps. But the most effective
combination if you don't already have a good set of headphones.
Since I already have a good ANR headset I'm trying another path...
I'm using a pair of Communication Earplugs made by CEP-USA for the military
underneath my CrossCountrys (bypassing the CrossCountry's speakers).
Why? The earplug design is the same as the ClarityAloft - and - in my opinion,
better attenuation than the best ANR headsets, and cheaper. The CrossCountry
mic is just fine. I get an $800 ANR headset without paying $800.
Also, even though the Communication Earplugs are really quiet,
I have noticed that in an aircraft covering the skull around the ear with a
GOOD (i.e., high passive attenuation) noise-attenuating headset or
industrial ear defenders makes a difference.
I don't know why, but suspect it may have something to do with interrupting
alternate transmission paths into the inner ear through the soft tissues and
bones
surrounding the ear.
Paul, rather than try and find a new pair of headsets, why don't you try a pair
of
Comm. Earplugs underneath your 25XLs? Cost - about $140 and a little assembly.
A lot cheaper than dropping $600-800 on a ?better? headset,
and it will work better for your Europa.
If you can stand wearing earplugs for extended periods, give it a try.
If you find you can't, you're only out $140.
Shaun
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