Fancy noise cancelling phones

[Tubetec]

So a buddy dropped me over his noise cancelling 300 euro plus headphones.

It seems like his daughter and her friends got her hands on them ,twisted one headphone in the wrong direction and damaged the flimsy hinge , on top of that one of the drive units is open circuit ,but the built in amplifier is still alive .

It seems like inside are two microphones one pointing outside the and another picking up the signal right next to the drive unit .
even though its only working in one channel ,I can hear the sound  and to be fair its piss poor. A single aaa cell powers the noise cancelling and what has to be a miserable power amplifier .

Anyway I rang the well known North American speaker companies help line , turn's out they will not supply parts ,what they will do is take the old headphones back and send out a brand new set for 130 euros . Meanwhile on ebay I can get a pair of chineese drive units same spec as the original more or less , 2.50 euros ,free postage . The sound is distorted from these things to begin with ,a crap chineese drive unit isnt gonna make em much worse . So now its not even worth B*** offering a  repair service ,its a five minute job to pop out the driver and resolder .This situation seems to be becoming the norm now, sell sell sell, but if you want spares kiss our ass ,and buy again .

 

[Jarno]

Keen on finding out if they do any processing of the signal picked up by the microphones before inverting it and mixing with the music. Probably just a bit of filtering.

 

[Tubetec]

Hi Jarno ,it looks fairly simple in there, what ever its doing its analog . Things are back together now ,but Ill post a pic of the guts next time.  One headphone has the two mics and amp board built in ,so the sound cancelling part works  in mono . Surely if each side had its own music minus  ambient noise signal the whole thing would work much better .
The gratefull dead employed funny noise cancelling mics in the 70's ,the idea being they had two small shotgun mics side by side ,the vocalist sang in to one while the other picked up ambient stage noise ,simply flipping the phase of one of the mics and mixing it with the other gives some reduction in spill ,but comb filtering could certainly occur ,and create its own frequency responce anomilies. I sometimes see cyclists wearing noise canceling phones ,seems like a very stupid and dangerous thing to do, spacial awareness of possible road hazzards is competely screwed up ,even with normal headphones peoples ability to opperate a vehicle safely is massively compromised ,there ought to be a law ......

 

[abbey road d enfer]

The gratefull dead employed funny noise cancelling mics in the 70's ,the idea being they had two small shotgun mics side by side ,the vocalist sang in to one while the other picked up ambient stage noise ,simply flipping the phase of one of the mics and mixing it with the other gives some reduction in spill ,but comb filtering could certainly occur ,and create its own frequency responce anomilies.

Not only the Dead; that was a widely used technique in the 70's. They did not realise that the principle was as good as cardioid mics are. In fact a dual-diaphragm cardioid condenser mic does exactly the same. Comb filtering is not more an issue than in a single-diaphragm cardioid mic, where the directivity pattern is the result of sound travelling from the front to the back.
Assuming the scond microphone would only pick ambient and ignore the singer's voice was plain stupid.

 

[Jarno]

Hi Jarno ,it looks fairly simple in there, what ever its doing its analog . Things are back together now ,but Ill post a pic of the guts next time.  One headphone has the two mics and amp board built in ,so the sound cancelling part works  in mono . Surely if each side had its own music minus  ambient noise signal the whole thing would work much better .
The gratefull dead employed funny noise cancelling mics in the 70's ,the idea being they had two small shotgun mics side by side ,the vocalist sang in to one while the other picked up ambient stage noise ,simply flipping the phase of one of the mics and mixing it with the other gives some reduction in spill ,but comb filtering could certainly occur ,and create its own frequency responce anomilies. I sometimes see cyclists wearing noise canceling phones ,seems like a very stupid and dangerous thing to do, spacial awareness of possible road hazzards is competely screwed up ,even with normal headphones peoples ability to opperate a vehicle safely is massively compromised ,there ought to be a law ......

Thanks, yes, that makes sense. Not sure why cyclists would wear them to be honest, that noise cancelling works below 1kHz (and even if that) but not above, because of phase issues, especially if they place two microphones on one side of the headphones. Being a cyclist myself, most noise is wind noise of the helmet, especially the straps. They even have little "cat's ears" to reduce turbulence around the straps and prevent noise.
https://www.amazon.de/cat-ears-Classic-Radfahren-Wind-Rauschreduktion/dp/B01M1FCNVS

Must say that despite it not being a very good idea, I regularly cycle with headphones, I am on the bike about 6 hours or more every week, and it sometimes is a bit tedious. But then, we have a lot of separate cycling lanes in NL, so you don't have cars wizzing by very closely. But I always make sure to keep the volume low, so I still am aware of my surroundings.

 

[Tubetec]

Thanks Abbey,

Well Jarno ,your in the right place for cycling ,lovely flat straight roads ,and of course the special cycle paths . If their lucky here cyclists ave a small strip between the road and the pavement ,if there not lucky they have to tough it out with cars and lorries on the road.

 

[JohnRoberts]

For OP probably find the broken wire(s) is easiest path.

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For riding bike with headphones don't try that where I live. No dedicated bike lanes here in (poor) nowhere MS.

As it is I ride on back roads to avoid as much car/truck traffic as I can, but the two lane roads, without paved shoulders, are not wide enough for two vehicles and me, so I have to be very road aware of traffic. I have a good rear view mirror but can generally hear the tire noise from traffic in either direction before I can see them.

I wear a helmet and have generally adapted to ignore whatever wind noise that causes. In very cold weather I wear face mask and ear muffs.

JR

PS: My pet peeve is when I do have the occasional 2 way traffic and some little old lady slows down, presumably to help me... 99.9% of the time I can negotiate 2 way traffic without losing too much momentum if they maintain their normal speeds, but the little old lady's slowing down or even stopping (to watch me crash?) can be unpredictable and dangerous forcing me to bail off the road. 

Pet peeve #2 is when people in cars/trucks wave me to cross in front of them... why in the world would I ever do that?