On 1/19/2012 8:20 PM, RichD wrote:
A noise canceling headphone consists of a headphone,
plus an external microphone fed to an inverting input,
right?
Why does that cost $40 extra?
--
Rich
You stock headphone doesn't have a power amp. For the noise cancelling
to work, it has to have an amplifier in it, so it is more than just
adding a microphone. A good system will have a delay line scheme rather
than just sum an external microphone.
I've had the original NCT headphones. OK, but it used a 9V battery (bad)
and the foam rotted (very bad). I had another brand for a while, but the
amp was noisy.
It is far cheaper just to get some etymotics and not have to cancel
noise in the first place.
http://www.etymotic.com/
The patent expired, so these are much cheaper nowadays. You no longer
have to buy direct either.
No extra battery required since it just blocks the noise rather than
tries to cancel it. It is aLways better to have a good sensor than tweak
a bad design with electronics.