weero

It indeed says so in the guidelines for the UA design. But I too have a hard time
to believe this. As the noise cancellation info has to be accurate to 1/4
wavelength (at least), for a 500 Hz sound that is some 15cms.
That is very hard to provide given the movement of the pax and the position
of the seats.

Pfaelzer

When you heard that the former President of Guatemala has stolen the lavatory of the presidential palace when leaving office, everything can be true these days...

weero

Fortunately, I haven't heard that one mmsteidl,
so I am still inclined to give the LH pax the benefit of the doubt.

slimothy

Finding someone with skinny arms is important in getting to the jack in the new C seats.

The standard 2-prong adaptor works well--just make sure that you don't separate it from the headphone cable in-flight or when you're trying to remove the cable.

I don't think the LH headphones have active noise cancellation built into them. They seem to mix in the third channel into the left and right to get the noise cancelling effect.

chapinpirulin

Not just the lavatory. He took everything from our people. And when he left the White House all furniture, decoration and all the fittings were gone. Now Interpol is looking for him and hopefully will find him in his hideaway in Mexico.

flysurfer

I KNEW you would intentionally misread it, so I didn't change it. However, I was worried that it took you so long. Been traveling? W/o FlyNet?

Anyway, we all know from our own experience that pax steal stuff from lavatories (mouthwash, lotion etc.). As for stealing from the galleys, I have believe what pursers told me and other FTers, and I can't see any reason to doubt their accounts.

flysurfer

Again, I was counting on you, the engineer, to provide some educated insight. After all, you must be useful for SOMETHING in here, don't you?

So how can we resolve the contradiction? Is UA simply pretending that the 3rd prong provides noise cancellation info in order to avoid the HP to be stolen, as they would be useless w/o the "NC info"? Any other conspiracy theories?

Then again, I remember that the UA NC HP were really bad when I used them. Maybe that's because the HPs get such inadequate information?

htb

Care to share the reason for your assessment?

HTB.

flysurfer

Too complicated.

We need to look for a cheap solution involving cheating, low quality and marketing blah.

weero

Spot on - was in Perth and took the midnight flight back to Sydney. So that
means a working day in the West and then cold and heartless isolation aboard
a brand new A330. Generally, I am not fond of the design of the airbusses
(that stumpy nose and the rigid aisle design so that your seat jumps up and
down when someone stampedes down the aisle) but this one's just perfect.
Quiet, smooth, and pretty. Like it better than the 777.
No seriously, it never occured to me. It's like stealing airplane headphones -
dirty used stuff thousands had in their hands and does not fit anywhere. And
mouthwash costs maybe 5 bucks and offers a reasonable chance to to spill on
one's handluggage...

weero

Gaining momentum again? I fear that your MoJo is not only coming back but it's
about to take over the boat .
I though about that too but then they are so ugly that they probably bound
to stay on the bird.
The only one I could think of is that they feed the main frequency of the
engine noise to the headphone which is capable to shifting it in a way to
minimize the volume ... but that would require almost the same amount of
circuitry than a 'full' noise cancellation board and offer a much lesser quality.
They are indeed not very good. But getting the phase information wrong
by say more than 20cm could actually make the noise level higher than not
having any circuitry.
Flying to States today, so will try if I can open such a headphone without
ruining it.
Now how will I get a screwdriver and a set of pliers on that plane ...?

flysurfer

Famous last words...

weero

Ok, won't try it.
Fork and toothpick will have to do then...

SleepOverGreenland

based on
In a few words:
Phase shifts would make this very complicated, since each noise frequence has it's own wavelength.

htb

Risking to completely hijack this thread...

Yes, this is exactly how noise cancelling phones work. A microphone picks up the noise very close to the ear. A noise cancelling circuit calculates the required phase shift and mixes the result with the music signal.

With Bose this circuitry is built into the headphone. The phones on the airplane don't seem to have any circuitry built-in. They must have microphones, however, otherwise noise cancelling wouldn't work (the noise must be recorded very close to the ears). Therefore to me it's quite reasonable to assume that the third prong is the stereo microphone.

This has the nice side effect to keep the headphones cheap and pointless to steal.

HTB.