Noise Canceling Headphones...switch to noise adding?

Noise cancelling headphones must be measuring the sound inside the ear cup, subtracting what should be there - the music - and then playing the rest in antiphase.

Or equivalently, measuring the sound outside the cup, applying a known transform representing the effect the cup has on sound, and then playing the result in antiphase.

In neither case is reversing the phase going to give you sound inside the cup that corresponds to the sound outside.

Sylvia.

No, but I've never had to.

I use moulded plugs with air tubes leading to acoustic drivers. I have the volume quite low, because the plugs block most of the noise anyway.

The plugs are not absolutely quite, and as long as the volume isn't loud, I can still get some road noise. Certainly horns and truck engines.

I really don't see the point of it, why use noise-cancelling ears if you're just going to re-introduce said noise back in again? Do you have any control over the cancelling circuitry? If so, I suppose you could reduce the cancelling signal a bit, so it doesn't cancel as much as it otherwise would.

I'd be wary of filtering here though, the filter would destroy the validity of the feedback signal making it useless. If you *really* want filtering, then you could filter the environment, and feed that back in (separate to the cancelling portion), though, as above I really don't see that proving useful.

This whole no headphones while driving BS needs some rethinking. Road safety cannot depend on the driver's ability to hear traffic noises.

There is no restriction on posessing a D/L if deaf. I can drive a Harley with open pipes or a truck with enough gearbox/engine noise to mask an approaching siren. Or a Bently with enough insulation that I can't hear one either.

Don't forget the wind noise. I used to travel about 1.5 hours on regular basis, most of that on a freeway. I could barely hear my own engine that was located between my legs uninsulated, let alone the car next to me that you wouldn't hear standing next to it.

Basically, I had choice, I could get to my destination hearing all the noise, perhaps a bit of traffic in built up areas, and result in a screaming headache when I get there, or not.

Also, I'm half deaf as well. (a neurological issue). This makes it difficult for me to descern a valid signal from background noise. The plugs allow me able to hear the headphones at a civilised volume, wereas, normal headphones (noise cancelling or not) the volume would have to be so loud it would make things worse.

Depend? No. But the more information you receive about the goings-on in your driving environment, the better it must be. And a motorcyclist is particularly vulnerable if there is an accident.

Sylvia.

In Europe it's illegal to use headphones when driving a bike ciao Ban .

I agree, although my bike has no engine on it.

The volume on my 'noise' source is low enough to be wiped out entirely by local traffic - can't hear it within 100 feet of a truck engine. I also only use one ear for this, not both.

I suspect that the actual problem is the noise from the motorcycle.

RL

Neither do four of mine. :-)

Bicycle noise is very very different from motorcycle noise. You get to hear every little bit of traffic noise. Wind noise is mostly a non-issue, and even when you *think* it's loud, it probably isn't.

Then there's motorcycle noise. You're travelling a LOT faster. Yes, yes, I've done around 55mph on my bicycle, but that's the exception to the rule, it's not a routine thing.

It's a far cry from spending hours on the freeway at ~70mph. THAT'S noise.

Can deaf people drive cars/bikes?