8
$\begingroup$

My first headset used passive noise reduction (i.e. padding) and when I - very quickly - upgraded to an ANR headset, my instructor recommended keeping the passive one "in case you ever fly something with an open cockpit". I can't remember if he gave me an explanation, but he definitely said that passive headsets "worked better" in an open cockpit.

I haven't flown anything open so I've never had the chance to put this to the test, but is it (or was it ever) true?

$\endgroup$
  • $\begingroup$ When I used passive NR headset, my CFI said that it is a good choice as I can hear different engine sounds and relate those to how the airplane is behaving. $\endgroup$ – Farhan Dec 10 '14 at 17:49
  • $\begingroup$ @farhan, that doesn't disappear with ANR. They just sound different, they aren't cancelled entirely. No ANR headset has a fast enough processor (or enough data) for that. $\endgroup$ – egid Dec 12 '14 at 16:43
  • $\begingroup$ @egid I cannot argue as I never used an ANR headset. $\endgroup$ – Farhan Dec 12 '14 at 22:18
10
$\begingroup$

First we should see how active noise reduction works. The simplest definition would be:

Active Noise Cancelling uses electric signals to reduce unwanted sounds.

The following picture on Active noise control depicts it in a simple manner:

Noise Cancelling

Then we can see what unwanted sounds ANR can actually reduce. As mentioned in A Guide To Buying An Aviation Headset:

ANR headsets work best at frequencies below about 400-450 Hertz. This represents the normal frequency range for speech, and also much propeller and exhaust noise is in this region. ANR headsets are therefore a significant advantage where intelligibility of transmissions is affected by engine and propeller noise.

In general, ANR Headsets offer greater hearing protection in high-noise environments but will do little to reduce noise at higher frequencies such as wind or airflow noise.

In a flying airplane (even in a slow flight), wind flow would be quite high. This PDF (page 1, paragraph 3) states:

The wind noise spectrum is dominated by the lower frequencies (< 500 Hz), although at 27 mph when saturation is present, the wind noise level can be greater than 60 dB SPL at 8 kHz.

Since passive noise control is sound reduction by noise-isolating materials such as insulation, sound-absorbing tiles, or a muffler rather than a power source, in an open cockpit, passive NR headsets work better than active NR headsets.

$\endgroup$
4
$\begingroup$

I fly a "open cockpit" flex-wing microlight. I also wear an simple full face helmet that is separate to my headsets. I fly relatively long flights with many being over 4 hours. I have also flown for 15.5 hours in a single day in the microlight.

Passive headsets (from differing manufacturers) would often leave a ringing in my ears. After a flight, it would be a minute or two before I could actually hear people speaking to me. R/T in flight was often difficult to hear.

The difference an ANR headset makes at the end of a flight is night and day. No ringing in the ears. Can hear people speaking to me fine. ATC is heard loud and clear.

As for hearing noise the aircraft engine makes, etc, ANR doesn't get rid of all noise, but it does stop you going deaf, so you can at least hear the subtle changes in the engines tone.

$\endgroup$
-4
$\begingroup$

I would never use active cancelling for two reasons:

  1. Simplicity. Doing anything that involves more complexity, batteries, wires, etc, is a bad idea. Keep things simple.

  2. You want to hear everything. The more you hear, the better. If something is wrong with the engine, you want to know that immediately, not find it out later when the plane turns into a brick. The point of the headphones is just to turn down the noise to tolerable levels, not eliminate it. When flying, hearing noises is good.

$\endgroup$
  • 3
    $\begingroup$ This answer seems to be mostly commentary, and does not really address the question asked. $\endgroup$ – NathanG Dec 13 '14 at 13:46
  • $\begingroup$ @NathanG: The question is about preferences, so is actually asking for opinions. If this are backed up by clear reasoning, I wonder why it wouldn't address the question. The answer could be more specific on the particulars of open cockpits, though. $\endgroup$ – Peter Kämpf Dec 14 '14 at 20:17
  • 3
    $\begingroup$ You DON'T want to hear everything. Long term exposure to high noise levels will damage your hearing. Importantly, this damage is cumulative (the longer you are exposed to the loud noise, the more likely and more profound the damage to your hearing will be). And here is the kicker: The loss of hearing won't be apparent for many years. Slowly in your later years your hearing will just go bad. Protect your hearing! Use ANR headsets when you can. $\endgroup$ – Skip Miller Dec 16 '14 at 20:42
  • $\begingroup$ @SkipMiller On leaving the air force, I was subjected to a discharge medical, I believe it's something to do with lessening the chance of future litigation. My service history was not made available to the various examiners to ensure that there was no bias. After my hearing test, the examiner asked if I had ever worked on Vulcans, which I had. I asked how he knew. He showed me the graph of my hearing frequency response which showed a large dip on a part of the chart (memory is dull but I recall it was near the lower end) which apparently is common amongst ex-Vulcan ground handlers. $\endgroup$ – Simon Apr 13 '16 at 21:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.