David Clarke Reviews

"G.R. Patterson III" wrote:

ANR can be designed to work on any frequency. I suggest your company might want to
check out the Bose ANR headphones (nonaviation). They seem to block out all
frequencies. Great hearing protectors in a noisy environment.

We were told by the manufacturer that they wouldn't make them for higher
frequencies, since there was risk of increasing noise levels at certain
frequencies. As the wavelengths get shorter, there are problems with
resonances within the earcups.

As far as headsets for noisy environments, the earcups themselves
attenuate higher frequency noises. The idea of ENR is to provide
attenuation at the low frequencies the passive earcups won't handle.

Well, I have six pairs of DC's.
My first two were acquired in 1981, two pairs of H10-40's (electret
mic, wire bales).
Then, in 1995, I bought a pair of H10-13.4Y's for the kids.
In 1997, a buddy gave me a pair of H10-13.4's when he sold his airplane.
These headset are comfortable if you have a narrow head.
For wider heads, you will feel "clamped".
So DC came up with the H20-10 series.
The H20-10's have bigger earcups with an adjustment that has three
positions to adjust the width.

My original H10-40's were sent back to DC for overhaul two years ago. I
was getting stress-relief breaks in the cords at the plugs (pre-molded
relief design).

I have gel seals and "comfort covers" on all six pairs.

I have worn them for up to 14 hours with only slight discomfort at the
end of the flight.

I always use an intercom, but wish PM Engineering would modify one of
their existing portable units to accomodate six headsets.