🚀 go-pugleaf

In article <zhenya.722056566@syzygy> zhenya@socs.uts.edu.au ( The Firefox.) writes:
>Does anyone have any ideas about the best way to build a device that takes
>an input from an external microphone, shifts the signal 180 degrees out
>of phase, and then re-emits it with little loss of resolution of the
>waveform in the process?

This is another one of those dream projects, like the radar-gun jammer
and the commercial killer, that crops up frequently in this group.

If what you're trying to do is get yourself some relief from your sister's
piano lessons, or the equivalent, you can basically forget it.  To do this
in any practical way, the system's emitter has to be either very close to
the noise source or very close to your ear.  Experiments have been done
with both; so far the only practical result is (expensive) noise-cancelling
headphones for use in light aircraft.

Earplugs are cheaper and more effective than anything you can make.
-- 
MS-DOS is the OS/360 of the 1980s.      | Henry Spencer @ U of Toronto Zoology
              -Hal W. Hardenbergh (1985)|  henry@zoo.toronto.edu  utzoo!henry