[Angelo Campanella[_2_]]

wrote:
Now, using YOUR proposal, please explain to the gathered
audience how you would "superimpose the correcting
source and the original.) The original noise source is
the size of a 747. According to you, if you can superimpose
a second, out-of-phase 747-sized noise source on the
original you're done. So then only place I can put the
correcting source is NEXT to the 747, say at an average
distance of 100 feet, and place the person awaiting the
sonic remedy exactly in between the two.

Using the term "noise source" is not appropriate, as you point out it
is remote and complex.

What is always important (or the only action readily feasible) is that
in present day noise canceling devices, only one error microphone is
applied and it senses only the net noise arriving (from a complex
source) at this single listening position.

Higher order noise canceling systems (Plants?) use a sensor at one or
more of the noise sources to obtain precise frequency and phase
information, and via complex computation derive more accurate noise
cancellation, or can project such cancellation to a position that is
neither at the error microphone nor at the canceling loudspeaker.

Perhaps someone here might care to educate us on these signal
processing algorithms.

Angelo Campanella