I know there has been a thread to this before in this nGroup,(must have been in 2001)
but I wasn't able to find a discrete circuit soving my noise problems.
So:
I've got to do lots of homework, have a personal hobby that needs lots of silence and am quite a lover of
silence by the way.

Does anyone know a circuit able to invert the phase of an audio signal comming directly from one or even two
piezo microphones (i could also use dynamic ones, it doesn't matter) and to supply it to headphones?
(that's what they call active noise cancellation, I hope)

Inverting operation amplifiers arent't that hard to build (See
http://www.hardwarebook.net/circuit/misc/OpAmpInv.html), but as I'm not used to building audio circuits, I'd
like someone with some experience in that (microphone amplifiers would be neccessary, I suppose..) to write me
back
sincerly
Marcus M.

"Marcus Müller" wrote ...
Does anyone know a circuit able to invert the phase of an
audio signal comming directly from one or even two
piezo microphones (i could also use dynamic ones, it
doesn't matter) and to supply it to headphones?
(that's what they call active noise cancellation, I hope)

It is not as simple as that.
There appear to be a growing number of active noise
cancelling headphone products available at consumer
prices. I would consider those before attempting to
build. (Unless you are seeking a particularly challenging
electro-acoustic-DSP project!)

"Marcus Müller" wrote ...
Does anyone know a circuit able to invert the phase of an
audio signal comming directly from one or even two
piezo microphones (i could also use dynamic ones, it
doesn't matter) and to supply it to headphones?
(that's what they call active noise cancellation, I hope)

It is not as simple as that.
There appear to be a growing number of active noise
cancelling headphone products available at consumer
prices. I would consider those before attempting to
build. (Unless you are seeking a particularly challenging
electro-acoustic-DSP project!)

"Marcus Müller" wrote ...
Does anyone know a circuit able to invert the phase of an
audio signal comming directly from one or even two
piezo microphones (i could also use dynamic ones, it
doesn't matter) and to supply it to headphones?
(that's what they call active noise cancellation, I hope)

It is not as simple as that.
There appear to be a growing number of active noise
cancelling headphone products available at consumer
prices. I would consider those before attempting to
build. (Unless you are seeking a particularly challenging
electro-acoustic-DSP project!)

"Marcus Müller" wrote ...
Does anyone know a circuit able to invert the phase of an
audio signal comming directly from one or even two
piezo microphones (i could also use dynamic ones, it
doesn't matter) and to supply it to headphones?
(that's what they call active noise cancellation, I hope)

It is not as simple as that.
There appear to be a growing number of active noise
cancelling headphone products available at consumer
prices. I would consider those before attempting to
build. (Unless you are seeking a particularly challenging
electro-acoustic-DSP project!)