Passive ANRs: when things go bad!

[rubberprune]

It may be an isolated case, but my Lightspeed Zulus ran out of batteries inflight and the resulting passive audio was distressingly like listening to people speaking underwater. No amount of radio volume would improve the clarity and I felt on the verge of being a safety liability in the sky. I trained on DC headsets and I remember the audio was a battle at times, particularly in a poorly sealed Cessna, but the drop from crystal clear ANR to Passive 'mud' was so much worse than I remember. I am thinking it must be the Zulus and I am reconsidering returning the headset.

Unless there is something I need to do to use them in a passive mode?

Can anyone relate to this experience? Do your Zulus work well enough in Passive Mode - i.e. when off?

Cheers, rubber

[Tinstaafl]

Many ANR headsets with their ANR function disabled perform worse than passive headsets when it comes to noise deadening. A benefit of ANR is that active sound reduction can compensate for using lighter materials whilst maintaining good, or even better than passive, noise reduction. Lose ANR and you can be left with a headset that isn't optimised for passive sound reduction, unlike the design of passive headsets.

[Time Traveller]

Some ANR headsets you do need to turn off when the batteries start to go flat, otherwise the flat battery interferes with the audio.

[172driver]

With the BOSE-X, while the passive attenuation isn't the greatest, there certainly is no loss in audio quality. So far have never run out of batteries, the above relates to testing it, i.e. switching the ANR off on purpose. No idea if a dud battery would create a problem.

[dublinpilot]

I've a set of DC ANRs.

When the batteries go, there is more engine external noise which makes hearing ATC a little harder. The clarity of the audio isn't reduced, it's just that the aircraft noise is louder.

If the ANR is left turned on while the batteries are gone, I get an anoying clicking type sound (not dissimilar to the ticking often heard on a radio when a mobile phone is nearby) but again the clarity of the audio itself is not disminished.

dp

[Rod1]

On the Bose you get plenty of warning from a red flashing light and you could change them in seconds. I have been flying with Bose X for years and although I keep a spare set of batteries handy I have never needed then in flight.

Rod1

[Jan Olieslagers]

Am I missing something or are batteries only required for active noise reduction?

[SEP Flyer]

Am I missing something or are batteries only required for active noise reduction?

Yes. My Bose X came with two sets of leads - a dual plug with battery holder for most of the planes I fly, and a six pin plug with volume controller only, for planes fitted with aircraft powered headsets. Once in a blue moon I have forgotten to switch on the battery powered lead and only realise a while into the flight - the headphones still work, it's all just a tad noisier!

[soay]

Originally Posted by Jan Olieslagers

Am I missing something or are batteries only required for active noise reduction?

Yes, batteries are only required for ANR, and the title of this thread ("Passive ANR") is an oxymoron.

[TCU]

Learned that lesson early on with my Zulu's although to be honest not to the point of being a safety issue, just a bit annoying. As a result:

1. I always remove the batteries after use and carry a spare set in the hard box
2. I always carry my old DC headset

[rubberprune]

Thanks guys for your helpful input.

1. I agree the Zulus are not made of a material that isolates well when passive. This is not surprising as they are so lightweight, which I like.
2. I now have a spare pair of batteries in the headset case.
3. A back-up pair of DCs is a good suggestion. These could be used by a passenger, of course, until they are needed by the PIC!

Try this experiment: plug your headset into your home stereo. Is it comparable to a good pair of home headphones?

I plugged my Zulus into my home stereo (ie no engine noise) and tuned into a classical FM station. ANR on - beautiful clear stereo. ANR off - very dull and unclear, and in my opinion unacceptable for communication.
Next I will borrow a passive set (say DC) and compare them side by side.

Cheers, rubber